WO2018170775A1 - Electrical quantity meter, current-sampling calibration circuit and method of calibration - Google Patents

Abstract

A electrical quantity meter, a current-sampling calibration circuit thereof and a method of calibration. The electrical quantity meter (30) comprises a sensing resistor (Rsense), a voltage sampler and a current-sampling calibration circuit. An input end of the voltage sampler connects to two ends of the sensing resistor (Rsense). The current-sampling calibration circuit comprises a battery (BAT), a first switch (SW1), a second switch (SW2), a calibration enabling circuit (41), a current source (42) and a controller (43). The second switch (SW2) and the current source (42) are connected to the battery (BAT) and the sensing resistor (Rsense) in parallel. The calibration enabling circuit (41) generates and outputs a second status signal to the second switch (SW2). When the second switch (SW2) is closed, the current source (42), the battery (BAT) and the sensing resistor (Rsense) form a circuit, and the controller (43) calculates a calibration resistance value of the sensing resistor (Rsense) according to a current value of the current source (42) and a sampling value of the voltage sampler. When the first switch (SW1) is closed, the battery (BAT), the sensing resistor (Rsense) and a load (RL) form a circuit, and the controller (43) calculates an electricity quantity according to the calibration resistance value.

Description

Fuel gauge and its current collecting calibration circuit and calibration method Technical field

The invention mainly relates to a fuel gauge, in particular to a current collection calibration circuit and a calibration method of a fuel gauge.

Background technique

因此放电电量就可以表示为：Figure 1 is an electrical schematic diagram of a conventional fuel gauge. Referring to FIG. 1, the fuel gauge includes a battery BAT, a switch SW, a resistor Rsense, an amplifier 11, an analog-to-digital converter (ADC) 12, 13, an accumulator 14, and a time base circuit 15. The current is collected by detecting the voltage across the resistor Rsense. The resistor Rsense is a measuring resistor, which is a mΩ class current-sense resistor. The resistor RL is the system load. The battery BAT discharges the system load RL by turning on the switch SW. When the system is operating normally, the current loop includes battery BAT, switch SW, resistors Rsense, and RL. Assuming that the loop current is I ₀ , the instantaneous voltage drop across the resistor Rsense is Vs(t)=I ₀ (t)×Rsense, and the fuel gauge 10 continuously detects the voltage difference Vs across the resistor Rsense and passes it through the amplifier 11 and The ADC 13 is converted to a digital value Current, and then accumulated, and the accumulated result is in units of Vh (volt-hour). Accumulating the quantized Vs is equivalent to integrating it

Therefore, the discharge capacity can be expressed as:

It can be seen from the above equation that the deviation of the resistance Rsense will cause the deviation of the power calculation.

2 is a welded structure of a resistor in the fuel gauge shown in FIG. 1. As shown in FIG. 2, when the resistance of the resistance Rsense is tens of milliohms, the welding resistance Rsolder is introduced during soldering. The value of Rsolder sometimes reaches milliohms, so the soldering impedance greatly increases the measurement error. Therefore, the existing fuel gauge has a problem that the current detection result has a large deviation. In addition, the resistance itself will have manufacturing variations, and this part of the deviation will also cause deviations in the current measurement results.

Summary of the invention

The technical problem to be solved by the present invention is to provide a current collecting and calibrating circuit in the fuel gauge, which can be used to adjust the error of the measuring resistor, thereby improving the accuracy of the current collecting of the fuel gauge.

In order to solve the above technical problem, the present invention provides a current collection calibration circuit in a fuel gauge, including a fuel gauge, including a measurement resistor, a voltage sampler, a power accumulator, and a current collection calibration. a circuit, an input end of the voltage sampler is connected to the two ends of the measuring resistor, and an output end of the voltage sampler is connected to the electric quantity accumulator, the current collecting and calibrating circuit comprises a battery, a first switch, a second switch, a calibration enabling circuit a current source and a controller, the battery is connected in series with the measuring resistor, and is connected in parallel with the load through the first switch, the first switch is opened and closed by the control of the first state signal; the second switch, the current source And the battery and the measuring resistor are connected in parallel; wherein the calibration enabling circuit generates a second state signal and outputs to the second switch, the second switch is opened and closed by the control of the second state signal; wherein When the two switches are closed, the current source, the battery and the measuring resistor form a loop, and the controller calculates a calibration resistance value of the measuring resistor according to the current value of the current source and the sampling value of the voltage sampler; when the first When the switch is closed, the battery, the measuring resistor and the load form a loop, and the controller uses the calibration resistor value to perform the power calculation.

In an embodiment of the invention, the first status signal is a power on state signal of the device where the fuel gauge is located.

In an embodiment of the invention, the calibration enable circuit generates the second status signal according to a shutdown state signal of the device in which the fuel gauge is located.

In an embodiment of the invention, the calibration enable circuit generates the second state signal according to a shutdown state signal of the device in which the fuel gauge is located, and one of an in-position signal and a power stabilization signal of the battery.

In an embodiment of the invention, the calibration enable circuit further detects a calibration flag and generates the second state signal when the calibration flag is set.

In an embodiment of the invention, the current acquisition calibration circuit further includes a register for storing a calibration resistance value of the measurement resistor, the register being coupled to the controller.

The invention also provides a current collecting and calibrating circuit of the fuel gauge, the current collecting and calibrating circuit comprises a battery, a measuring resistor and a voltage sampler, wherein the battery is connected in series with the measuring resistor, and the input end of the voltage sampler is connected to the measuring resistor End, wherein the current collection calibration circuit comprises a battery, a first switch, a second switch, a calibration enable circuit, a current source and a controller, the battery is connected in series with the measuring resistor, and the first switch is connected in parallel with the load, the first a switch is opened and closed by the control of the first state signal, the current source is connected in parallel with the battery and the measuring resistor, and the controller is connected to the voltage sampler; wherein the calibration enabling circuit generates the second The status signal is output to the second switch, and the second switch is opened and closed by the control of the second status signal; wherein when the second switch is closed, the current source, the battery and the measuring resistor form a loop, And the controller is based on the current value of the current source and the electricity The sampled value of the pressure sampler calculates the calibration resistance value of the measured resistance.

In an embodiment of the invention, the calibration enable circuit generates the second status signal according to a shutdown state signal of the device in which the fuel gauge is located.

In an embodiment of the invention, the calibration enable circuit generates the second state signal according to a shutdown state signal of the device in which the fuel gauge is located, and one of an in-position signal and a power stabilization signal of the battery.

In an embodiment of the invention, the calibration enable circuit further detects a calibration flag and generates the second state signal when the calibration flag is not set.

In an embodiment of the invention, the current acquisition calibration circuit further includes a register for storing a calibration resistance value of the measurement resistor, the register being coupled to the controller.

The invention also provides a current collecting and calibrating method for a fuel gauge, the fuel gauge comprising a measuring resistor, a voltage sampler, a power accumulator and a current collecting calibration circuit, wherein an input end of the voltage sampler is connected to the two ends of the measuring resistor, An output of the voltage sampler is coupled to the power accumulator, the first switch being opened and closed by the control of the first state signal, the current collection calibration circuit comprising a battery, a first switch, a second switch, and a current source, the battery In series with the measuring resistor, and connected in parallel with the load through the first switch, the second switch, the current source and the battery, the measuring resistor are connected in parallel; wherein the first switch is controlled to be opened and closed by the first state signal The second switch is opened and closed by the control of the second state signal, the method comprising the steps of: providing the second state signal to close the second switch, the current source, the battery and the measuring resistor forming a loop; Calculating a calibration resistance value of the measurement resistor according to a current value of the current source and a sample value of the voltage sampler; providing the first state signal The first switch is closed, the battery, the load resistor and the measurement circuit composition, and the controller uses the resistance value the calibration amount calculation.

In an embodiment of the invention, the first status signal is a power on state signal of the fuel gauge.

In an embodiment of the invention, the second status signal is provided according to a shutdown status signal of the device in which the fuel gauge is located.

In an embodiment of the invention, the second status signal is provided according to a shutdown status signal of the device in which the fuel gauge is located, and one of the in-position signal and the power stabilization signal of the battery.

In an embodiment of the invention, the method includes: after obtaining the calibration resistance value, setting a calibration flag, wherein the calibration flag is detected, and the second is generated when the calibration flag is not set. Status signal.

In an embodiment of the invention, when the calibration flag is not set, if the power-on vector of the device where the fuel gauge is located is received, the second state signal is still provided, and the booting process is suspended.

The above-mentioned fuel gauge and the current calibration circuit thereof eliminate the error of the mounting and the resistor itself by calibrating the actual value after the precision resistor is mounted, and write the calibration value into the register of the battery voltage domain, and call the normal operation. The value is calculated to optimize the fuel gauge calculation accuracy. The current calibration method of the above embodiment of the present invention ensures the timing of calibration and the timing of power calculation by the strict process design, which ensures the accuracy of calibration and the accuracy of current calculation.

BRIEF abstract

Features and capabilities of the present invention are further described by the following examples and the accompanying drawings.

Figure 1 is an electrical schematic diagram of a conventional fuel gauge.

2 is a welded structure of a resistor in the fuel gauge shown in FIG. 1.

3 is an electrical schematic diagram of a fuel gauge according to an embodiment of the present invention.

4 is an electrical schematic diagram of a fuel gauge according to another embodiment of the present invention.

Fig. 5 is an electrical schematic diagram of a fuel gauge according to still another embodiment of the present invention.

6 is a flow chart of a current collection calibration method according to an embodiment of the present invention.

7 is a flow chart of a current collection calibration method according to another embodiment of the present invention.

FIG. 8 is a flow chart of a current collection calibration method according to still another embodiment of the present invention.

Preferred embodiment of the invention

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims.

In the following description, numerous specific details are set forth in the description of the invention, and the invention may be practiced otherwise.

The words "a", "an", "the" and "the" In general, the terms "comprising" and "comprising" are intended to include only the steps and elements that are specifically identified, and the steps and elements do not constitute an exclusive list, and the method or device may also include other steps or elements.

Embodiments of the present invention describe a current acquisition calibration circuit and a calibration method in a fuel gauge for modifying the error of the measured resistance, particularly the error introduced by the resistor during mounting and the error of the resistor itself. The fuel gauge of the present invention can be used to measure battery capacity, and thus can be widely used in various portable electronic devices.

3 is an electrical schematic diagram of a fuel gauge according to an embodiment of the present invention. Referring to FIG. 3, the fuel gauge 30 of the present embodiment includes a measurement resistor Rsense, an amplifier 31, an analog-to-digital converter (ADC) 32, 33, an accumulator 34, a time base circuit 35, a current source 36, and a calibration. The circuit 40 is enabled. The amplifier 31 and the ADC 33 form a voltage sampler. The input of the amplifier 31 is connected to both ends of the measuring resistor Rsense, and the output terminal is connected to the input terminal of the ADC 33. The output of ADC 33 is coupled to accumulator 34. The accumulator 34 and the time reference circuit 35 constitute a power accumulator.

The current collection calibration circuit 40 includes a battery BAT, a first switch SW1, a second switch SW2, a calibration enable circuit 41, a current source 42, and a controller 43. The battery BAT is connected in series with the measuring resistor Rsense and in parallel with the load RL through the first switch SW1. The second switch SW2, the current source 42 and the battery BAT, and the measuring resistor Rsense are connected in parallel. The nominal resistance of the measuring resistor Rsense is Rsense, however due to the introduction of the welding resistance value Rsolder, the actual resistance value Rsns is the sum of Rsense and Rsolder. Further, considering the difference between the actual value Rsense' of the measuring resistor Rsense and the nominal value, the actual resistance value Rsns is the sum of Rsense' and Rsolder. Current source 42 has a current Ical. In order to ensure the accuracy of the calibration, Ical needs to be stable and has a low error. For example, the error of Ical is ±1%.

The fuel gauge of this embodiment has two states of power calculation and resistance calibration. To this end, a first state signal and a second state signal are provided, respectively corresponding to the two states, for controlling the first switch SW1 and the second switch SW2. The power calculation is usually performed after the device where the fuel gauge is turned on. Therefore, the power-on state signal of the device where the fuel gauge is located is selected as the first state signal, and is supplied to the first switch SW1. The first switch SW1 is turned off and closed by the control of the power-on state signal, that is, when the power-on state signal display device is turned on, the first switch SW1 is closed, otherwise the first switch SW1 is turned off. When the device where the fuel gauge is turned off, the accuracy of the calibration can be ensured. Therefore, the shutdown state signal of the device where the fuel gauge is located is selected as the second state signal and is supplied to the second switch SW2. The calibration enable circuit 41 generates a second state signal according to the off state and outputs it to the second switch SW2. The second switch SW2 is turned off and closed by the control of the second state signal, that is, when the shutdown state signal display device is turned off, the second switch SW2 is closed, otherwise the second switch SW2 is turned off.

When the second switch SW2 is closed, the current source 42, the battery BAT and the measuring resistor Rsense are composed Loop. A voltage sampler consisting of amplifier 31 and ADC 33 will acquire the voltage Vcal across the measurement resistor Rsense. At this time, the actual measured resistance value can be calculated in the controller 43 as Rsns=Vcal/Ical. This resistance value can be used as the calibration resistance value.

When the first switch SW1 is closed, the battery BAT, the measuring resistor Rsense and the load RL form a loop. At this time, the controller 43 can calculate the electric quantity by using the calibration resistance value, and the process of calculating the electric quantity is already an existing technology, and is not expanded here.

Preferably, a register 44 is provided for storing the calibration resistance value. Register 44 is coupled to controller 43 so that controller 43 can access register 44. Thus, when the fuel gauge is in the power calculation state, its value REGcal can be called from the register 44 to calculate the power.

4 is an electrical schematic diagram of a fuel gauge according to another embodiment of the present invention. Referring to FIG. 4, the fuel gauge 30 of the present embodiment includes a measurement resistor Rsense, an amplifier 31, an analog-to-digital converter (ADC) 32, 33, an accumulator 34, a time base circuit 35, a current source 36, and a calibration. The circuit 40 is enabled. The amplifier 31 and the ADC 33 form a voltage sampler. The input of the amplifier 31 is connected to both ends of the measuring resistor Rsense, and the output terminal is connected to the input terminal of the ADC 33. The output of ADC 33 is coupled to accumulator 34. The accumulator 34 and the time reference circuit 35 constitute a power accumulator.

The current collection calibration circuit 40 includes a battery BAT, a first switch SW1, a second switch SW2, a calibration enable circuit 41, a current source 42, and a controller 43. The battery BAT is connected in series with the measuring resistor Rsense and in parallel with the load RL through the first switch SW1. The second switch SW2, the current source 42 and the battery BAT, and the measuring resistor Rsense are connected in parallel. The nominal resistance of the measuring resistor Rsense is Rsense, however due to the introduction of the welding resistance value Rsolder, the actual resistance value Rsns is the sum of Rsense and Rsolder. Further, considering the difference between the actual value Rsense' of the measuring resistor Rsense and the nominal value, the actual resistance value Rsns is the sum of Rsense' and Rsolder. Current source 42 has a current Ical. In order to ensure the accuracy of the calibration, Ical needs to be stable and has a low error. For example, the error of Ical is ±1%.

The fuel gauge of this embodiment has two states of power calculation and resistance calibration. To this end, a first state signal and a second state signal are provided, respectively corresponding to the two states, for controlling the first switch SW1 and the second switch SW2. The power calculation is usually performed after the device where the fuel gauge is turned on. Therefore, the power-on state signal of the device where the fuel gauge is located is selected as the first state signal, and is supplied to the first switch SW1. The first switch SW1 is turned off and closed by the control of the power-on state signal, that is, when the power-on state signal display device is turned on, the first switch SW1 is closed, otherwise the first switch SW1 is turned off. The device where the fuel gauge is located is turned off When the accuracy of the calibration is more ensured, the shutdown state signal of the device where the fuel gauge is located is selected as the second state signal and supplied to the second switch SW2. The present embodiment is different from the previous embodiment in that the calibration enable circuit 41 generates a second state signal based on the battery in-position signal and the off-state signal. At this time, the calibration enable circuit 41 can be implemented as an AND gate. In other words, calibration is only performed when the battery is in place and the device where the fuel gauge is located is off.

In another variation, the battery in-position signal can be replaced with a power supply stabilization signal, that is, calibration is performed only when the power supply is stable and the device in which the fuel gauge is located is off.

Fig. 5 is an electrical schematic diagram of a fuel gauge according to still another embodiment of the present invention. Referring to FIG. 5, the fuel gauge 30 of the present embodiment includes a measurement resistor Rsense, an amplifier 31, an analog-to-digital converter (ADC) 32, 33, an accumulator 34, a time base circuit 35, a current source 36, and a calibration. The circuit 40 is enabled. The amplifier 31 and the ADC 33 form a voltage sampler. The input of the amplifier 31 is connected to both ends of the measuring resistor Rsense, and the output terminal is connected to the input terminal of the ADC 33. The output of ADC 33 is coupled to accumulator 34. The accumulator 34 and the time reference circuit 35 constitute a power accumulator.

The current collection calibration circuit 40 includes a battery BAT, a first switch SW1, a second switch SW2, a calibration enable circuit 41, a current source 42, and a controller 43. The battery BAT is connected in series with the measuring resistor Rsense and in parallel with the load RL through the first switch SW1. The second switch SW2, the current source 42 and the battery BAT, and the measuring resistor Rsense are connected in parallel. The nominal resistance of the measuring resistor Rsense is Rsense, however due to the introduction of the welding resistance value Rsolder, the actual resistance value Rsns is the sum of Rsense and Rsolder. Further, considering the difference between the actual value Rsense' of the measuring resistor Rsense and the nominal value, the actual resistance value Rsns is the sum of Rsense' and Rsolder. Current source 42 has a current Ical. In order to ensure the accuracy of the calibration, Ical needs to be stable and has a low error. For example, the error of Ical is ±1%. In addition, the value of the current Ical can be set to 100 mA or hundreds of mA, as needed.

The fuel gauge of this embodiment has two states of power calculation and resistance calibration. To this end, a first state signal and a second state signal are provided, respectively corresponding to the two states, for controlling the first switch SW1 and the second switch SW2. The power calculation is usually performed after the device where the fuel gauge is turned on. Therefore, the power-on state signal of the device where the fuel gauge is located is selected as the first state signal, and is supplied to the first switch SW1. The first switch SW1 is turned off and closed by the control of the power-on state signal, that is, when the power-on state signal display device is turned on, the first switch SW1 is closed, otherwise the first switch SW1 is turned off. When the device where the fuel gauge is turned off, the accuracy of the calibration can be ensured. Therefore, the signal of the shutdown state of the device where the fuel gauge is located is selected. The second state signal is supplied to the second switch SW2. The present embodiment differs from the previous embodiment in that the current acquisition calibration circuit 40 further includes a register 45 that holds a calibration flag. After the controller 43 obtains the calibration resistance value, the calibration flag is set (eg, set to 1). The calibration enable circuit 41 first detects the calibration flag bit, and when the calibration flag bit is not set, generates a second state signal based on the battery in-position signal and the off-state signal. At this time, the calibration enable circuit 41 can be implemented as an AND gate having three signal inputs. That is to say, calibration is performed only when the calibration is not performed, the battery is in place, and the device where the fuel gauge is located is turned off.

In another variation, the battery in-position signal can be replaced with a power supply stabilization signal, that is, calibration is performed only when the power supply is stable and the device in which the fuel gauge is located is off.

6 is a flow chart of a current collection calibration method according to an embodiment of the present invention. Referring to FIG. 6, when the current management calibration method of the embodiment is in the power-on reset state, the following steps are performed:

In step 61, it is detected whether the device where the fuel gauge is located is in a shutdown state, and if yes, proceeds to step 62, otherwise continues to wait;

In step 62, it is determined whether there is a boot vector, if yes, proceed to step 66, otherwise proceed to step 63; where the boot vector is an event that can cause the device of the fuel gauge to be powered on, such as pressing a power button, starting charging, etc.;

In step 63, the resistance value calibration is performed; the specific calibration process can refer to the foregoing embodiment, and is not expanded here;

At step 64, the calibration resistor value is written to the register;

In step 65, it is determined again whether there is a boot vector, if yes, proceed to step 66, otherwise continue to wait;

At step 66, the power is turned on, and the fuel gauge performs a power calculation;

At step 67, the value of the register is called for calculation when performing the power calculation;

At step 68, the power calculation is performed cyclically.

7 is a flow chart of a current collection calibration method according to another embodiment of the present invention. Referring to FIG. 7, when the current management calibration method of the embodiment is in the power-on reset state, the following steps are performed:

In step 71, it is detected whether the device where the fuel gauge is located is in a shutdown state, and if yes, proceeds to step 62, otherwise continues to wait;

In step 72, it is determined whether the calibration flag is 1, if it is 1 indicating that the calibration has been performed, proceeds to step 73, otherwise proceeds to step 74;

In step 73, it is determined whether there is a boot vector, if yes, proceed to step 77, otherwise continue to wait; where the boot vector is an event that can cause the device of the fuel gauge to be powered on, such as pressing a power button, starting charging, etc.;

In step 74, the resistance value calibration is performed; the specific calibration process can refer to the foregoing embodiment, and is not expanded here;

At step 75, the calibration resistance value is written to the register and the calibration flag is set;

In step 76, it is determined again whether there is a boot vector, if yes, proceed to step 66, otherwise continue to wait;

At step 77, the power is turned on, and the fuel gauge performs a power calculation;

At step 78, the value of the register is called for calculation when performing the power calculation;

At step 79, the power calculation is performed cyclically.

FIG. 8 is a flow chart of a current collection calibration method according to still another embodiment of the present invention. Referring to FIG. 8, the current collection calibration method of the embodiment is that when the power management chip is in the power-on reset state, the following steps are performed:

In step 81, it is determined whether the battery is in place, if yes, then proceeds to step 83, otherwise proceeds to step 82;

In step 82, it is determined whether the power supply is stable, if yes, then proceeds to step 83, otherwise returns to step 81;

In step 83, it is detected whether the device where the fuel gauge is located is in a shutdown state, and if yes, proceeds to step 84, otherwise continues to wait;

In step 84, it is determined whether the calibration flag is 1, if it is 1 indicates that the calibration has been performed, proceeds to step 85, otherwise proceeds to step 86;

In step 85, it is determined whether there is a boot vector, if yes, proceed to step 89, otherwise continue to wait; where the boot vector is an event that can cause the device of the fuel gauge to be powered on, such as pressing a power button, starting charging, etc.;

At step 86, the resistance value calibration is performed; the specific calibration process can refer to the foregoing embodiment, and is not expanded here;

At step 87, the calibration resistance value is written to the register and the calibration flag is set;

At step 88, it is again determined whether there is a boot vector present, if yes, then proceeds to step 66, otherwise Continue to wait;

In step 89, the power is turned on, and the fuel gauge performs a power calculation;

At step 90, the value of the register is called for calculation when performing the power calculation;

At step 91, the power calculation is performed cyclically.

In addition, when the power is turned on and the power is turned on, the load current is increased to affect the calibration value. Therefore, the calibration should be performed under shutdown conditions. In order to avoid the startup accuracy during the execution of the resistance value calibration, the embodiment shown in Fig. 7 can be further optimized to the embodiment shown in Fig. 9. Referring to FIG. 9, the current collection calibration method of the embodiment is that when the power management chip is in the power-on reset state, the following steps are performed:

In step 1001, it is detected whether the device where the fuel gauge is located is in a shutdown state, and if yes, proceeds to step 62, otherwise continues to wait;

In step 1002, it is determined whether the calibration flag is 1, if it is 1 indicating that the calibration has been performed, proceeds to step 1003, otherwise proceeds to step 1004;

In step 1003, it is determined whether there is a boot vector, if yes, proceed to step 1011, otherwise continue to wait; where the boot vector is an event that can cause the device of the fuel gauge to be powered on, such as pressing a power button, starting charging, etc.;

In step 1004, it is determined whether there is a boot vector exists, if yes, then proceeds to step 1008, otherwise proceeds to step 1005;

In step 1005, the resistance value calibration is performed; the specific calibration process can refer to the foregoing embodiment, and is not expanded here;

At step 1006, the calibration resistance value is written to the register and the calibration flag is set;

In step 1007, it is determined again whether there is a boot vector, if yes, proceed to step 66, otherwise continue to wait;

At step 1008, performing a resistance value calibration;

In step 1009, a boot process is performed;

At step 1010, the calibration resistance value is written to the register and the calibration flag is set;

In step 1011, the power is turned on, and the fuel gauge performs a power calculation;

In step 1012, the value of the register is called when performing the power calculation;

At step 1013, the power calculation is performed cyclically.

That is, when it is determined in step 1004 that the boot vector exists, the boot process is not immediately executed, but the predetermined time (for example, 100 ms) is delayed, and the resistance value calibration is performed in step 1008 for a predetermined time, and then the boot process is executed in step 1009. .

The fuel gauge and the current calibration circuit of the above embodiment of the present invention eliminate the error of the mounting and the resistor itself by calibrating the actual value after the precision resistor is mounted, and write the calibration value into the register of the battery voltage domain, during normal operation. This value is called for power calculation, which optimizes the calculation accuracy of the fuel gauge. The current calibration method of the above embodiment of the present invention ensures the timing of calibration and the timing of power calculation by the strict process design, which ensures the accuracy of calibration and the accuracy of current calculation.

While the invention has been described with respect to the embodiments of the present invention, it will be understood by those skilled in the art Various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (17)

A fuel gauge includes a measuring resistor, a voltage sampler, a power accumulator, and a current collecting calibration circuit, wherein an input end of the voltage sampler is connected to the two ends of the measuring resistor, and an output end of the voltage sampler is connected to the electric quantity accumulator. , The current collection calibration circuit includes a battery, a first switch, a second switch, a calibration enable circuit, a current source, and a controller. The battery is connected in series with the measurement resistor, and is connected in parallel with the load through the first switch, the first switch is received Disconnecting and closing the first state signal, the second switch, the current source and the battery, the measuring resistor are connected in parallel; wherein the calibration enabling circuit generates a second state signal and outputs the second state switch to the second switch The second switch is opened and closed by the control of the second state signal; When the second switch is closed, the current source, the battery and the measuring resistor form a loop, and the controller calculates a calibration resistance value of the measuring resistor according to the current value of the current source and the sampling value of the voltage sampler; When the first switch is closed, the battery, the measuring resistor and the load form a loop, and the controller uses the calibration resistance value to perform a power calculation. The fuel gauge of claim 1 wherein the first status signal is a power on state signal of the device in which the fuel gauge is located. The fuel gauge of claim 1 wherein the calibration enable circuit generates the second status signal based on a shutdown status signal of the device in which the fuel gauge is located. The fuel gauge according to claim 1, wherein the calibration enabling circuit generates the second state signal according to a shutdown state signal of the device in which the fuel gauge is located, and one of an in-position signal and a power stabilization signal of the battery. . A fuel gauge according to claim 3 or 4, wherein the calibration enable circuit further detects a calibration flag and generates the second state signal when the calibration flag is set. The fuel gauge of claim 1 wherein the current acquisition calibration circuit further comprises a register for storing a calibration resistance value of the measurement resistor, the register being coupled to the controller for the controller to access the register. A current collecting calibration circuit for a fuel gauge, the fuel gauge comprising a measuring resistor and a voltage sampler, wherein an input end of the voltage sampler is connected to the two ends of the measuring resistor The current collection calibration circuit includes a battery, a first switch, a second switch, a calibration enable circuit, a current source, and a controller. The battery is connected in series with the measurement resistor, and is connected in parallel with the load through the first switch, the first switch Disconnected and closed by the control of the first state signal, the current source and the battery, the measuring resistor are connected in parallel, the controller is connected to the voltage sampler; wherein the calibration enabling circuit generates the second state signal And outputting to the second switch, the second switch being opened and closed by the control of the second state signal; When the second switch is closed, the current source, the battery and the measuring resistor form a loop, and the controller calculates a calibration resistance value of the measuring resistor according to the current value of the current source and the sampling value of the voltage sampler; When the first switch is closed, the battery, the measuring resistor and the load form a loop, and the controller uses the calibration resistance value to perform a power calculation. The current acquisition calibration circuit of claim 7 wherein the calibration enable circuit generates the second status signal based on a shutdown status signal of the device in which the fuel gauge is located. The current collecting calibration circuit according to claim 7, wherein the calibration enabling circuit generates the second according to a shutdown state signal of the device where the fuel gauge is located, and one of an in-position signal and a power stabilization signal of the battery. Status signal. The current acquisition calibration circuit of claim 8 or 9, wherein the calibration enable circuit further detects a calibration flag and generates the second state signal when the calibration flag is not set. The current acquisition calibration circuit of claim 7 further comprising a register for storing a calibration resistance value of the measurement resistor, the register being coupled to the controller. A current collecting calibration method for a fuel gauge, the fuel gauge comprising a measuring resistor, a voltage sampler, a power accumulator, and a current collecting calibration circuit, wherein an input end of the voltage sampler is connected to the two ends of the measuring resistor, the voltage sampler The output terminal is connected to the power accumulator, the first switch is opened and closed by the control of the first state signal, the current collecting calibration circuit comprises a battery, a first switch, a second switch and a current source, the battery and the measuring resistor Connected in series, and connected in parallel with the load through the first switch, the second switch, the current source and the battery, the measuring resistor are connected in parallel; wherein the first switch is opened and closed by the control of the first state signal, the second The switch is opened and closed by the control of the second state signal, the method comprising the steps of: Providing the second state signal to close the second switch, the current source, the battery and the measuring resistor forming a loop; Calculating a calibration resistance value of the measurement resistor according to a current value of the current source and a sample value of the voltage sampler; The first state signal is provided to close the first switch, the battery, the measuring resistor and the load form a loop, and the controller uses the calibration resistance value to perform a power calculation. The current collecting calibration method according to claim 12, wherein the first state signal is a power-on state signal of the fuel gauge. The current collecting calibration method according to claim 12, wherein the second state signal is provided according to a shutdown state signal of the device in which the fuel gauge is located. The current collection calibration method according to claim 12, wherein the second state signal is provided according to a shutdown state signal of the device in which the fuel gauge is located, and one of an in-position signal and a power stabilization signal of the battery. The current collection calibration method according to claim 14 or 15, further comprising: After obtaining the calibration resistance value, a calibration flag is set, The calibration flag is detected and the second status signal is generated when the calibration flag is not set. The current collecting and calibrating method according to claim 16, wherein when the calibration flag is not set, if the power-on vector of the device where the fuel gauge is located is received, the second state signal is still provided, and the second state signal is temporarily suspended. Process.

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