JPH06339229A - Microcomputer - Google Patents

Abstract

PURPOSE:To provide a microcomputer which can accurately judge the states of quick charging, normal charging, etc., of a storage battery and accurately show charging/discharging state of the battery by detecting an offset voltage of an operational amplifier. CONSTITUTION:An output of an operational amplifier when two inputs of operational amplifiers 16, 17 are set to the same potential is previously A/D-converted. Then, an output of the amplifiers when an analog signal is applied to the amplifiers 16, 17 is A/D-converted. Relative relationship of A/D-converted information of the former and the latter is detected to accurately judge the states of quick charging, normal charging, etc., of a storage battery 1. Accordingly, charging/discharging state of the battery 1 can be accurately shown.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-computer capable of judging the polarity of an analog signal generated according to the state of a peripheral device (for example, the charging / discharging state of a storage battery) and accurately informing the state of the peripheral device. Regarding computers.

[0002]

2. Description of the Related Art Portable V recording system such as VHS, 8 mm
Although it has been a long time since the TR was released, these portable VTRs are equipped with a storage battery (battery) to operate because commercial power sources cannot be used directly. This storage battery is charged by connecting it to a commercial power source, and is discharged by connecting it to a portable VTR. However, recently, in consideration of user's usability, the storage battery is charged in a plurality of charging states. LED
There is also a charging device that can be checked by sequentially turning on, and a portable VTR that has a function of checking the discharge state of a storage battery by sequentially turning off a plurality of LEDs. This function includes two types of operational amplifiers that perform inverting amplification and non-inverting amplification, a resistor connected between the ground terminal of the storage battery and the input terminals of the two types of operational amplifiers, and a microcomputer including an AD converter. It can be realized by combining. Specifically, when the storage battery is connected to a commercial power source, a charging current flows from the positive terminal to the negative terminal of the storage battery, so that a negative analog voltage appears on the non-grounded side of the resistor. This analog voltage is applied to two types of operational amplifiers, but only one of them is inverted and amplified. The inverted and amplified analog voltage is applied to the microcomputer, and the polarity is judged and digitally converted and integrated with the digital information indicating the elapsed charging time. From this, the LEDs are sequentially turned off based on the polarity and the integrated information. I am going to do it. On the contrary, when the storage battery is connected to the portable VTR, a discharge current flows from the negative terminal of the storage battery to the positive terminal side, so that a positive analog voltage appears on the non-grounded side of the resistor. This analog voltage is applied to two types of operational amplifiers, but is only non-inverted and amplified by the other operational amplifier. The non-inverted and amplified analog voltage is applied to a microcomputer, the polarity is determined, and also digitally converted and integrated with digital information indicating the discharge elapsed time. From this, the portable VTR is based on the polarity and the integrated information. It is designed to turn off the provided LEDs in sequence.

When the storage battery is removed from the commercial power source and the portable VTR, a charging / discharging current does not flow between the positive terminal and the negative terminal of the storage battery, so that an analog voltage of 0 V appears on the non-grounded side of the resistor. . This analog voltage is applied to two types of operational amplifiers, and is inverted and non-inverted, but remains 0 volt. This analog voltage is applied to the microcomputer, and it is determined that there is no charging / discharging. Therefore, the LED is turned on and off as it is.

[0004]

The input difference (offset voltage) when both input terminals of the operational amplifier are set to the same potential.
Is 0 volt in the ideal state, but in reality, the elements forming the operational amplifier are affected by factors such as temperature, power supply voltage, and change over time, and do not reach 0 volt. Therefore, the operational amplifier performs operational amplification in a state in which the offset voltage is added to the input voltage, and the true output voltage cannot be obtained.
Therefore, even though the storage battery is fully charged, the LE
There is a problem that only one D is off, or only one LED is on even though the storage battery has completed discharging, and the user confirms the charge / discharge state of the storage battery. Was deadly on.

Therefore, the present invention uses an operational amplifier whose output voltage with respect to the offset voltage has a positive polarity to detect the offset voltage in advance, thereby rapidly charging the storage battery,
It is an object of the present invention to provide a microcomputer capable of accurately determining the state of ordinary charging and the like and accurately informing the charging / discharging state of a storage battery.

[0006]

The present invention has been made to solve the above problems, and is characterized in that it has first and second input gates to which an analog signal is applied, The first and second reference gates to which a reference signal is applied and the first input gate and the first reference gate are complementarily conducted or cut off, and the second input gate and the second reference gate are complementary. An input switching register in which switching data for conducting or cutting off is set, a signal that has passed through the first input gate or the first reference gate and the reference signal, and the comparison result is inverted and amplified. One operational amplifier, a second operational amplifier that compares the signal that has passed through the second input gate or the second reference gate with the reference signal, and non-inverts and amplifies the comparison result, and the first and second operations Amplifier operation A first and a second switching element to which a power source is applied, a power supply switching register in which switching data for selectively turning on and off the first and the second switching element is set, and the first and second operations An AD converter for converting the output signal of the amplifier into a digital signal, and the first and second inputs based on the output signals of the first and second operational amplifiers when the first and second reference gates are conducted. And a control circuit for offset-correcting the output signals of the first and second operational amplifiers when the gate is conductive and determining the polarity of the analog signal.

[0007]

According to the present invention, two of the first and second operational amplifiers are provided.
The operational amplification output when the inputs are at the same potential is AD-converted in advance. After that, the operational amplification output when the analog signal is applied to the first and second operational amplifiers is AD-converted. Then, the relative relationship between the AD conversion information of the former and the latter is detected to accurately determine the states of the rapid charging of the storage battery, the normal charging, and the like. Therefore, the charging / discharging state of the storage battery can be accurately notified.

[0008]

The details of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a microcomputer having an offset compensation function of the present invention. It should be noted that FIG. 1 shows a charging device that sequentially lights a plurality of LEDs corresponding to the charging state of the storage battery, or a plurality of LEDs corresponding to the discharging state of the storage battery.
In this example, a microcomputer is used for a portable VTR or the like having a function of sequentially turning off the lights.

In FIG. 1, (1) is a storage battery, one end of which is connected to a positive power supply terminal (2), the other end of which is grounded and which is connected to a negative power supply terminal (4) via a resistor (3). Has been done. That is, the storage battery (1) is connected to a commercial power source for charging, and connected to a portable VTR for discharging. (5-
1) to (5-3) are LEDs, which are turned on or off according to the charging / discharging state of the storage battery (1). (6)
Is a switch, and a storage battery (1) according to the user's request
This is to connect or disconnect the non-grounded side and the anode side of the LEDs (5-1) to (5-3). Specifically, when the closing of the switch (6) is detected by the CPU (described later), the LEDs (5-1) to (5-3) are turned on or off according to the elapsed time of charging / discharging "0". Alternatively, a drive signal of "1" is output from the driver described later. On the other hand, when the opening of the switch (6) is detected by the CPU, the LEDs (5-1) to (5-
The driver outputs a drive signal of all "1" for forcibly turning off 3). (7) and (8) are a feedback resistance and an input resistance, respectively, which determine the gain of the first operational amplifier described later. Similarly, (9) (1
0) is also a feedback resistance and an input resistance, respectively.
It determines the gain of the operational amplifier. These elements are externally connected to a microcomputer described later.

A dot-dash line (11) is a microcomputer, which is an LED according to the charging / discharging state of the storage battery (1).
It has a function of turning on or off (5-1) to (5-3). Inside the microcomputer (11), (12) and (13) are transmission gates (first and second input gates), one end of which is a resistor (3).
Connected to the non-grounded side of. Similarly, (14) (1
5) is also a transmission gate (first and second reference gates), one end of which is grounded. (16) is an operational amplifier (first operational amplifier) for performing inverting amplification, the inverting input terminal is connected to the output terminal via the feedback resistor (7) and the transmission gate (12) is provided via the input resistor (8). ) (14) is connected to the other end, and the non-inverting input terminal is grounded. Similarly, (17) is an operational amplifier (second operational amplifier) that performs non-inverting amplification, the non-inverting input terminal is connected to the other ends of the transmission gates (13) and (15), and the inverting input terminal is a feedback resistor ( It is connected to the output terminal via 9) and is grounded via the input resistor (10). (18) (19) are P-channel type MOS transistors (first and second switch elements), the source / drain path of which is a power supply Vdd and an operational amplifier (16).
It is inserted between the power supply terminal (17) and the power supply terminal. (20)
Is a ROM, which stores program data for the microcomputer (11) to perform arithmetic processing. (21) and (22) are registers (power supply switching registers)
And is connected to the gates of the MOS transistors (18) and (19) through the inverters (39) and (23). The registers (21) and (22) receive the decoding output of the program data of the ROM (20), and the switching data for selectively turning on or off the MOS transistors (18) and (19) are set. Similarly, (24) (25)
Is a register (input switching register), and register (2
4) is connected to the control terminal of the transmission gate (12) and is connected to the control terminal of the transmission gate (14) via the inverter (26), and the register (25) is connected to the control terminal of the transmission gate (13). At the same time, it is connected to the control terminal of the transmission gate (15) through the inverter (27). The registers (24) and (25) are ROM
Upon receiving the decoded output of the program data of (20), the switching data for complementarily turning on or off the transmission gates (12) and (13) is set. (28)
Is an AD converter, which converts the amplified output of the operational amplifiers (16) and (17) into an 8-bit digital signal. Reference numeral (29) denotes a CPU, which receives the decoded output of the program data in the ROM (20) and performs various logical operations. (30) is a RAM, which is an AD converter (2
The conversion information of 8) and the logical operation information of the CPU (29) are written and read. Reference numeral (31) is a driver for turning on or off the LEDs (5-1) to (5-3) in response to the logical operation output of the CPU (29).

FIG. 2 is a diagram showing a successive approximation type AD converter as an example of the AD converter (28). In FIG.
(32) is a resistor of 256 (= 2 ⁸ ) lines and has a power supply Vdd
And grounded in series. Denoted at (33) is a decoder, which has a resistance (3
The analog voltage appearing at the specific connection point of 2) is derived. The decoder (33) receives the output of the detector when the microcomputer (11) is initialized and derives a reference voltage of Vdd / 2 that appears at the connection midpoint of the resistor (32). . (34) and (35) are transmission gates, one end of which is connected to the output terminals of the operational amplifiers (16) and (17). The transmission gates (34) and (35) are connected to the ROM (2
It receives the decoding output of the program data of 0) and complementarily conducts or cuts off. (36) is a comparator, the inverting input terminal of which is connected to the decoder (33), and the non-inverting input terminal of which is the transmission gates (34) (3
5) is connected to the other end. Reference numeral (37) is a detector, which responds to the comparison output of the comparator (36) by a decoder (3
3) is controlled. Reference numeral (38) is an 8-bit shift register for sequentially shifting the comparison data of "0" or "1" output from the comparator (36) from the least significant bit to the most significant bit. Hereinafter, an example of the operation of FIG. 2 will be described.

First, when the microcomputer (11) is initialized and then an instruction to perform an AD conversion operation is executed, the magnitude relationship between the analog voltage and the reference voltage Vdd / 2 is compared by the comparator (36). . For example, when the comparison data of "0" is output from the comparator (36), the comparison data is set to the least significant bit of the shift register (38) and is applied to the detector (37), and the analog voltage is set to the reference voltage. A detection signal indicating that the voltage is smaller than Vdd / 2 is output from the detector (37). Next, when the detection signal is applied to the decoder (33), an intermediate voltage Vdd / 4 of 0 to Vdd / 2 is derived from the decoder (33), and the magnitude relationship between the analog voltage and the reference voltage Vdd / 4 is obtained. Comparator (3
Compared in 6). For example, when the comparison data of "1" is output from the comparator (36), the comparison data is set to the least significant bit of the shift register (38) and is applied to the detector (37), and the analog voltage is set to the reference voltage. Voltage Vdd /
A detection signal indicating that it is between 4 and Vdd / 2 is output from the detector (37). At this time, the comparison data of "0" at the beginning is shifted from the least significant bit of the shift register (38) to the least significant second bit. Next, when the detection signal at this time is applied to the decoder (33), Vdd / 4 to V
The intermediate voltage 3Vdd / 8 of dd / 2 is derived from the decoder (33), and the magnitude relationship between the analog voltage and the reference voltage 3Vdd / 8 is compared by the comparator (36). For example, when the comparison data of "0" is output from the comparator (36), the comparison data is set to the least significant bit of the shift register (38) and is applied to the detector (37), and the analog voltage is set as a reference. A detection signal indicating that the voltage is between Vdd / 4 and 3Vdd / 8 is output from the detector (37). At this time,
The first comparison data of "0" is shifted from the lower 2nd bit to the lower 3rd bit of the shift register (38), and the comparison data of "1" immediately after that is shifted from the least significant bit to the lower 2nd bit of the shift register (38). It has been shifted to the bit position.
After that, by repeating this operation, an 8-bit digital signal corresponding to the analog voltage can be generated.

The operation of FIG. 1 will be described below. For example, the case of using it for a charging device will be described. First, the storage battery (1) is connected to the power supply terminals (2) and (4) of the charging device, and the quick charge switch (not shown) is operated to connect the power supply terminal (2).
A DC voltage obtained by rectifying the commercial power supply is applied to (4). Then, the storage battery (1) starts rapid charging, and its charging current flows from the positive terminal to the negative terminal of the storage battery (1) and also to the resistor (3). Then, on the non-grounded side of the resistor (3), a negative analog voltage lower than that in normal charging appears.
On the other hand, the microcomputer (11) is initialized and the following operations are executed according to the initial program in the ROM (20).

First, a drive signal corresponding to the residual voltage of the storage battery (1) is output from the driver (31) and the LED (5-
1) to (5-3) are displayed according to the remaining voltage of the storage battery. In this state, the power supply switching register (21)
The switching data "1" and "0" are set in (22), and the power supply Vdd and the power supply terminal of the operational amplifier (16) are connected via the MOS transistor (18). At the same time, the switching data "0" is set in the input switching register (24), and the transmission gate (14) becomes conductive. That is, the microcomputer (11) is in the offset mode. At this time, the inverting input terminal and the non-inverting input terminal of the operational amplifier (16) are grounded, and ideally the operational amplifier (1
The output voltage of 6) should be 0 volt, but in reality, the element forming the operational amplifier (16) receives a factor (temperature change, aging change, power supply voltage, etc.) that causes the characteristics to change, and therefore the offset It never occurs to 0 volt. Therefore, the operational amplifier (16) generates a positive analog voltage according to the offset. This analog voltage is converted into an 8-bit digital signal Dost1 by the AD converter (28) and written in a specific address of the RAM (30). Thereafter, without changing the values of the power source switching registers (21) and (22), the switching data "1" is stored in the input switching register (24).
Is set and the transmission gate (12) becomes conductive. That is, the microcomputer (11) is in the normal mode. At this time, the negative analog voltage is inverted and amplified by the operational amplifier (16) according to the gain of the feedback resistor (7) / input resistor (8). This analog voltage is converted into an 8-bit digital signal Dopr1 by the AD converter (28),
It is written to a specific address in the RAM (30). Then, the digital signal D from the specific address of the RAM (30)
ost1 and Dopr1 are read out, and a digital signal (Dopr1-Dost1) that purely corresponds to only the negative-polarity analog voltage that does not include an offset is obtained. Based on this digital signal, the CPU (29) can determine that the analog voltage has a negative polarity and can surely detect that rapid charging is being performed. In this case, since the power supply Vdd and the power supply terminal of the operational amplifier (17) are cut off, the switching data of the input switching register (25) may have any value.

Next, the power source switching registers (21) and (22)
The switching data "0" and "1" are set to the power supply Vdd and the power supply terminal of the operational amplifier (17) are connected via the MOS transistor (19). At the same time, the switching data “0” is set in the input switching register (25) and the transmission gate (15) is turned on. That is, the microcomputer (11) becomes the offset mode again.
At this time, the inverting input terminal and the non-inverting input terminal of the operational amplifier (17) are grounded, and ideally the output voltage of the operational amplifier (17) should be 0 V, but in reality an offset occurs. It will never go to 0 volts. Therefore, the operational amplifier (17) generates a positive analog voltage according to the offset. This analog voltage is applied to the AD converter (2
In 8), converted to 8-bit digital signal Dost2, RA
It is written to a specific address of M (30). After that, without changing the values of the power supply switching registers (21) and (22), the switching data "1" is set in the input switching register (25) and the transmission gate (13) is turned on. That is, the microcomputer (11) is in the normal mode. At this time, the negative analog voltage is applied to the non-inverting input terminal of the operational amplifier (17), but since the inverting input terminal is grounded, an analog voltage of 0 volt is output from the operational amplifier (17). It This analog voltage is converted by the AD converter (28) into a digital signal Dopr2 of which all 8 bits are "0" and written in a specific address of the RAM (30). Then, the digital signals Dost2 and Dopr2 are read from the specific address of the RAM (30), and the difference signal (Dopr2-Dost2) is obtained. Since this difference signal is only the polarity inversion of the digital signal corresponding to the offset voltage, the CPU (29) can also determine from this difference signal that the analog voltage has a negative polarity. In this case,
Since the power supply Vdd and the power supply terminal of the operational amplifier (16) are cut off, the switching data of the input switching register (24) may have any value.

Then, when the storage battery (1) is continuously charged, the digital signal (Dopr1-Dost1) and the digital signal indicating the charging elapsed time are integrated, and the driver (31) of the driver (31) is responsive to the integrated information. Output is "1" to "0"
The LEDs (5-1) to (5-3) are sequentially turned on. From the above, the user can surely and easily confirm the state of charge of the storage battery (1).

When a fully charged storage battery (1) is connected to the power supply terminals (2) and (4) of a portable VTR or the like having the microcomputer shown in FIG. 1, the storage battery (1) starts discharging and discharges. Since a current flows from the resistor (3) to the positive terminal of the storage battery (1) through the negative terminal, a positive analog voltage appears on the non-grounded side of the resistor (3). This analog voltage is determined to be positive by repeating the offset mode and the normal mode described above. And LED over time
(5-1) to (5-3) are sequentially turned off.

From the above, by detecting the offset voltage of the operational amplifiers (16) and (17), the states of the storage battery (1) such as rapid charge and normal charge can be accurately determined, and the charge of the storage battery (1) can be determined. The discharge state can be accurately confirmed by using the display means such as LEDs (5-1) to (5-2).

[0019]

According to the present invention, temperature change, aging change,
By detecting the offset voltage of the first and second operational amplifiers that change due to factors such as power supply voltage fluctuations in advance and obtaining the true output voltage by subtracting the offset voltage from the input voltage, rapid charging of the storage battery, normal charging, etc. The state of can be accurately determined,
Further, there is an advantage that the charging / discharging state of the storage battery can be accurately known.

[Brief description of drawings]

FIG. 1 is a diagram showing a microcomputer of the present invention.

FIG. 2 is a diagram showing an example of an AD converter shown in FIG.

[Explanation of symbols]

(1) Storage battery (11) Microcomputer (12) (13) (14) (15) Transmission gate (16) (17) Operational amplifier (21) (22) Power supply switching register (24) (25) Input switching register ( 28) AD converter (29) CPU

Claims (2)

[Claims] 1. A first and a second to which an analog signal is applied
An input gate, first and second reference gates to which a reference signal is applied, the first input gate and the first reference gate are complementarily conducted or cut off, and the second input gate and the second reference gate An input switching register in which switching data for complementarily turning on or off the gate is set, and the signal passed through the first input gate or the first reference gate and the reference signal are compared, and the comparison result is compared. A first operational amplifier that performs inverting amplification; a second operational amplifier that compares the signal that has passed through the second input gate or the second reference gate with the reference signal and non-invertingly amplifies the comparison result; And first and second switch elements to which operating power of the second operational amplifier is applied, and a power source switching register in which switching data for selectively connecting or disconnecting the first and second switch elements is set. An AD converter for converting the output signals of the first and second operational amplifiers into digital signals, and the output signals of the first and second operational amplifiers when the first and second reference gates are conductive. Based on the first and second
A control circuit that offset-corrects the output signals of the first and second operational amplifiers when the input gate is turned on and determines the polarity of the analog signal. 2. A charge / discharge state of the storage battery is detected by applying analog voltages having different polarities to the first and second input gates according to charge / discharge of the storage battery and determining the polarity of the analog voltage. The microcomputer according to claim 1, characterized in that: