CN203658888U

CN203658888U - USB power supply compensating circuit and portable electronic equipment

Info

Publication number: CN203658888U
Application number: CN201320800662.8U
Authority: CN
Inventors: 孟晓鹏
Original assignee: TCL Tongli Electronics Huizhou Co Ltd
Current assignee: TCL Tongli Electronics Huizhou Co Ltd
Priority date: 2013-12-06
Filing date: 2013-12-06
Publication date: 2014-06-18
Anticipated expiration: 2023-12-06

Abstract

The utility model discloses a USB power supply compensating circuit and portable electronic equipment provided with the USB power supply compensating circuit. The USB power supply compensating circuit comprises a power input end, a first USB interface, a second USB interface, a first current-limiting module, a second current-limiting module, a current detecting module, a voltage detecting module and a compensation control module. According to the USB power supply compensating circuit, when the driving current required by external equipment is larger than the largest USB power supply current output by the first current-limiting module, the detection voltage output by the current detecting module is larger than the reference voltage preset by the voltage detecting module, the voltage detecting module controls the compensation control module to be switched off to enable the second current-limiting module to be enabled to output a compensation current to compensate the USB power supply current, and then the output USB power supply current can meet power supply requirements of the external equipment. Furthermore, due to the fact that the USB power supply current does not need to be increased with a high-power adapter or a large-current power panel, cost is reduced.

Description

USB power supply compensation circuit and portable electronic equipment

Technical Field

The utility model relates to a technical field of electronic equipment USB power supply especially relates to a USB power supply compensating circuit and portable electronic equipment.

Background

At present, most of portable electronic devices with USB interfaces use current-limiting chips to limit the supply current of the USB interfaces, and generally use the following two schemes:

(1) as shown in fig. 1, the USB power supply circuit uses a current-limiting chip U01 to limit current, and sets the total current of two USB paths to 1A, that is, the current of each USB path is set to 0.5A, and the current on the USB interfaces P1 and P2 is 0.5A. If the USB power supply circuit shown in fig. 1 is used, when a certain USB is plugged into an external device, for example, a Hard Disk Drive (HDD), a current of 1A is required to Drive the HDD, so that when another USB is also plugged into the HDD or another external device, the external device cannot be read because the Drive current is too small.

(2) As shown in fig. 2, the USB power supply circuit uses two current-limiting chips U01 and U02 to limit current, and this scheme can control the current of one USB path through one current-limiting chip, that is, the current-limiting chip U01 in fig. 2 controls the current of the USB interface P1 branch independently, and the current-limiting chip U02 controls the current of the USB interface P2 branch independently, so that the situation that a certain USB path cannot read external devices due to too small driving current or no driving current does not occur, and the problem existing in the first scheme is solved, but the USB power supply circuit shown in fig. 2 may have the following problems: when the output current of each current-limiting chip is limited to 1A, the two USB channels consume 2A of current in total, so the system needs to reserve 2A of current for the two USB channels, which puts higher requirements on the power supply of the whole system, needs a higher-power adapter, provides a higher-current power panel and the like, however, the cost is increased when the high-power adapter or the high-current power panel is manufactured.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a USB power supply compensating circuit and portable electronic equipment, when aiming at the increase of external equipment power supply demand, the USB supply current of automatic compensation satisfies different external equipment's USB power supply demand, simultaneously reduce cost.

In order to achieve the above object, the present invention provides a USB power supply compensation circuit, which includes a power input terminal, a first USB interface, a second USB interface, a first current limiting module for providing a USB power supply current, a second current limiting module for outputting a compensation current to compensate the USB power supply current, a current detection module for detecting the USB power supply current and outputting a detection voltage according to a detection result, a voltage detection module for detecting the detection voltage and outputting a corresponding detection signal according to the detection result, and a compensation control module for controlling whether the second current limiting module outputs the compensation current according to the detection signal; wherein,

the power supply input end is respectively connected with the input end of the first current limiting module, the input end of the second current limiting module and the input end of the compensation control module; the output end of the first current limiting module is respectively connected with the first USB interface, the second USB interface and the input end of the voltage detection module through the current detection module; the output end of the second current limiting module is respectively connected with the first USB interface and the second USB interface; and the control end of the compensation control module is connected with the output end of the voltage detection module, and the output end of the compensation control module is connected with the enabling end of the second current limiting module.

Preferably, the first current limiting module comprises a first current limiting chip, a first resistor and a first capacitor; the input pin and the enable pin of the first current limiting chip are both connected with the power supply input end, the current setting pin of the first current limiting chip is grounded through the first resistor, the ground pin of the first current limiting chip is grounded, and the output pin of the first current limiting chip is connected with the input end of the current detection module; one end of the first capacitor is connected with the power input end, and the other end of the first capacitor is grounded.

Preferably, the current detection module comprises a second resistor; the first end of the second resistor is connected with the output pin of the first current-limiting chip, and the second end of the second resistor is respectively connected with the power pin of the first USB interface, the power pin of the second USB interface and the input end of the voltage detection module.

Preferably, the voltage detection module comprises a comparator, a reference voltage input terminal, a first working voltage input terminal and a second working voltage input terminal; the positive power supply end of the comparator is connected with the first working voltage input end, the negative power supply end of the comparator is connected with the second working voltage input end, the in-phase input end of the comparator is connected with the reference voltage input end, the reverse phase input end of the comparator is connected with the second end of the second resistor, and the output end of the comparator is connected with the control end of the compensation control module.

Preferably, the compensation control module includes a switching element and a third resistor; the first end of the switch element is connected with the output end of the comparator, the second end of the switch element is connected with the enable end of the second current limiting module and is connected with the power supply input end through the third resistor, and the third end of the switch element is grounded.

Preferably, the switching element is a PNP triode, a base of the PNP triode is a first end of the switching element, an emitter of the PNP triode is a second end of the switching element, and a collector of the PNP triode is a third end of the switching element.

Preferably, the switching element is a PMOS transistor, a gate of the PMOS transistor is a first end of the switching element, a source of the PMOS transistor is a second end of the switching element, and a drain of the PMOS transistor is a third end of the switching element.

Preferably, the second current limiting module includes a second current limiting chip, a fourth resistor, and a second capacitor;

an input pin of the second current limiting chip is connected with the power supply input end, an enable pin of the second current limiting chip is connected with a second end of the switch element and is connected with the power supply input end through the third resistor, a current setting pin of the second current limiting chip is grounded through the fourth resistor, a ground pin of the second current limiting chip is grounded, and an output pin of the second current limiting chip is respectively connected with a power supply pin of the first USB interface and a power supply pin of the second USB interface; one end of the second capacitor is connected with the power input end, and the other end of the second capacitor is grounded.

The utility model also provides a portable electronic equipment, this portable electronic equipment includes USB power supply compensating circuit, this USB power supply compensating circuit includes power input end, first USB interface, second USB interface, is used for providing USB supply current's first current-limiting module, is used for exporting compensating current in order to compensate USB supply current's second current-limiting module, is used for detecting USB supply current and exports the current detection module of detection voltage according to the testing result, is used for detecting detection voltage and exports corresponding detection signal's voltage detection module according to the testing result to and be used for according to the compensation control module of whether compensation current is exported to the second current-limiting module of detection signal control; wherein,

The utility model provides a USB power supply compensating circuit, through first USB interface and/or second USB interface connection external equipment, output USB supply current provides required drive current for external equipment to read external equipment. When the driving current required by the external equipment is larger than the maximum USB supply current limited and output by the first current limiting module, the detection voltage output by the current detection module is larger than the reference voltage preset by the voltage detection module, the voltage detection module controls the compensation control module to be switched off, so that the second current limiting module enables and outputs the compensation current to compensate the USB supply current, the output USB supply current can meet the power supply requirement of the external equipment, a high-power adapter or a high-current power panel is not needed to increase the USB supply current, and the cost is reduced.

Drawings

FIG. 1 is a schematic circuit diagram of a USB power supply circuit in the prior art;

FIG. 2 is a schematic circuit diagram of another USB power supply circuit in the prior art;

FIG. 3 is a schematic block diagram of a preferred embodiment of the USB power compensation circuit of the present invention;

fig. 4 is a schematic circuit diagram of a USB power compensation circuit according to an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of another embodiment of the USB power compensation circuit of the present invention.

The objects, features and advantages of the present invention will be realized by the embodiments and will be further described with reference to the accompanying drawings.

Detailed Description

The technical solution of the present invention is further explained below with reference to the drawings and the specific embodiments of the specification. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The utility model provides a USB power supply compensation circuit.

Referring to fig. 3, fig. 3 is a schematic block diagram of a preferred embodiment of the USB power compensation circuit of the present invention.

In the preferred embodiment of the present invention, the USB power compensation circuit is applied to a portable electronic device (e.g., a mobile phone) having a USB interface, and can be connected to an external device (e.g., an HDD) via the USB interface to read the external device. The utility model discloses a USB power supply compensation circuit includes power input end VIN, first USB interface 10, second USB interface 20, first current limiting module 30, second current limiting module 40, current detection module 50, voltage detection module 60 and compensation control module 70. The first current limiting module 30 provides a USB power supply current, the second current limiting module 40 is configured to output a compensation current to compensate the USB power supply current, the current detecting module 50 is configured to detect the USB power supply current and output a detection voltage according to a detection result, the voltage detecting module 60 is configured to detect the detection voltage and output a corresponding detection signal according to the detection result, and the compensation control module 70 is configured to control whether the second current limiting module 40 outputs the compensation current according to the detection signal.

Wherein, the power input terminal VIN is respectively connected to the input terminal of the first current limiting module 30, the input terminal of the second current limiting module 40, and the input terminal of the compensation control module 70; the output end of the first current limiting module 30 is connected to the input ends of the first USB interface 10, the second USB interface 20 and the voltage detecting module 60 through the current detecting module 50; the output end of the second current limiting module 40 is connected with the first USB interface 10 and the second USB interface 20 respectively; the control terminal of the compensation control module 70 is connected to the output terminal of the voltage detection module 60, and the output terminal is connected to the enable terminal of the second current limiting module 40.

In this embodiment, the first USB interface 10 and/or the second USB interface 20 are connected to an external device, the first current limiting module 30 outputs a USB supply current to the first USB interface 10 and the second USB interface 20, and the USB power supply current is limited not to exceed the maximum USB power supply current preset by the first current limiting module 30, the USB power supply current output by the first current limiting module 30 to the first USB interface 10 and the second USB interface 20 flows through the current detecting module 50, the current detecting module 50 detects the USB power supply current output by the first current limiting module 30 to the first USB interface 10 and the second USB interface 20, and outputs a detection voltage to the voltage detection module 60 according to the detection result, the voltage detection module 60 outputs a corresponding detection signal according to the magnitude of the detection voltage to control the compensation control module 70 to be turned on or off, and then controls whether the second current limiting module 40 outputs the compensation current to compensate the USB supply current.

When the driving current required by the external device connected to the first USB interface 10 and/or the second USB interface 20 does not exceed the maximum USB power supply current limited by the first current limiting module 30, the detection voltage output by the current detection module 50 is smaller than the reference voltage preset by the voltage detection module 60, the voltage detection module 60 outputs a high-level detection signal to the compensation control module 70, and controls the compensation control module 70 to be turned on, so that the enabling of the second current limiting module 40 is turned off, and the second current limiting module 40 does not operate and does not output a compensation current. When the driving current required by the external device connected to the first USB interface 10 and/or the second USB interface 20 is greater than the maximum USB power supply current limited by the first current limiting module 30, the detection voltage output by the current detection module 50 is greater than the reference voltage preset by the voltage detection module 60, the voltage detection module 60 outputs a low-level detection signal to the compensation control module 70, and the compensation control module 70 is controlled to turn off, so that the second current limiting module 40 enables and outputs the compensation current to compensate the USB power supply current, and thus the USB power supply current output through the first USB interface 10 and/or the second USB interface 20 can meet the power supply requirement of the external device, and can drive the external device, so that the portable electronic device can read the external device.

Compared with the prior art, the utility model discloses a USB power supply compensating circuit, when the required drive current of external equipment is greater than the biggest USB supply current of first current-limiting module 30 restriction output, the detection voltage of current detection module 50 output is greater than the predetermined reference voltage of voltage detection module 60, voltage detection module 60 control compensation control module 70 is turn-offed, make second current-limiting module 40 enable and export the compensation current and compensate USB supply current, thereby make the USB supply current of output can satisfy the power supply demand of external equipment, and need not use high-power adapter or heavy current power supply board to increase USB supply current, and the cost is reduced.

Referring to fig. 4 again, fig. 4 is a schematic circuit diagram of a USB power compensation circuit according to an embodiment of the present invention.

In this embodiment, the first current limiting module 30 includes a first current limiting chip U1, a first resistor R1, and a first capacitor C1; an input pin IN1 and an enable pin EN1 of the first current-limiting chip U1 are both connected with a power supply input end VIN, a current setting pin ISET1 of the first current-limiting chip U1 is grounded via a first resistor R1, a ground pin GND1 of the first current-limiting chip U1 is grounded, and an output pin OUT1 of the first current-limiting chip U1 is connected with an input end of the current detection module 50; one end of the first capacitor C1 is connected to the power input terminal VIN, and the other end of the first capacitor C1 is grounded.

For example, if the first current-limiting chip U1 of the embodiment adopts a SY6280 chip, the limiting current value of the first current-limiting chip U1 is 6800/Rset1, where Rset1 is the resistance value of the first resistor R1. Therefore, the required maximum USB supply current can be set by adjusting the resistance value of the first resistor R1, and the USB supply current output by the first current limiting chip U1 is limited to 6800/Rset 1.

Specifically, the current detection module 50 includes a second resistor R2; a first end of the second resistor R2 is connected to the output pin OUT1 of the first current-limiting chip U1, and a second end of the second resistor R2 is connected to the power pin VCC1 of the first USB interface 10, the power pin VCC2 of the second USB interface 20, and the input end of the voltage detection module 60, respectively. The second resistor R2 is a current detection resistor, and when the first current-limiting chip U1 outputs different USB supply currents, different voltage differences are formed across the second resistor R2.

Specifically, the voltage detection module 60 includes a comparator U3, a reference voltage input REF, a first operating voltage input V + and a second operating voltage input V-; the positive power supply end of the comparator U3 is connected with a first working voltage input end V +, the negative power supply end of the comparator U3 is connected with a second working voltage input end V-, the non-inverting input end of the comparator U3 is connected with a reference voltage input end REF, the inverting input end of the comparator U3 is connected with the second end of the second resistor R2, and the output end of the comparator U3 is connected with the control end of the compensation control module 70.

Specifically, the compensation control module 70 includes a switching element Q1 and a third resistor R3; a first terminal of the switching element Q1 is connected to the output terminal of the comparator U3, a second terminal of the switching element Q1 is connected to the enable terminal of the second current limiting module 40, and is connected to the power input terminal VIN via a third resistor R3, and a third terminal of the switching element Q1 is grounded.

Specifically, the second current limiting module 40 includes a second current limiting chip U2, a fourth resistor R4, and a second capacitor C2.

An input pin IN2 of a second current-limiting chip U2 is connected with a power supply input terminal VIN, an enable pin EN2 of a second current-limiting chip U2 is connected with a second end of the switching element Q1 and is connected with the power supply input terminal VIN through a third resistor R3, a current setting pin ISET2 of the second current-limiting chip U2 is grounded through a fourth resistor R4, a ground pin GND2 of a second current-limiting chip U2 is grounded, and an output pin OUT2 of the second current-limiting chip U2 is respectively connected with a power supply pin VCC1 of the first USB interface 10 and a power supply pin VCC2 of the second USB interface 20; one end of the second capacitor C2 is connected to the power input terminal VIN, and the other end of the second capacitor C2 is grounded.

For example, if the second current-limiting chip U2 of the embodiment adopts a SY6280 chip, the limiting current value of the second current-limiting chip U2 is 6800/Rset2, where Rset2 is the resistance value of the fourth resistor R4. Therefore, the required maximum USB supply current can be set by adjusting the resistance value of the fourth resistor R4, and the USB supply current output by the second current-limiting chip U2 is limited to 6800/Rset 2.

As shown in fig. 4, the switching element Q1 in the compensation control module 70 is a PNP transistor, a base of the PNP transistor is a first terminal of the switching element Q1, an emitter of the PNP transistor is a second terminal of the switching element Q1, and a collector of the PNP transistor is a third terminal of the switching element Q1.

Referring to fig. 5 again, fig. 5 is a schematic circuit diagram of another embodiment of the USB power compensation circuit of the present invention.

Unlike the USB power compensation circuit shown in fig. 4, in a modified embodiment, as shown in fig. 5, the switching element Q1 in the compensation control module 70 is a PMOS transistor, the gate of the PMOS transistor is the first terminal of the switching element Q1, the source of the PMOS transistor is the second terminal of the switching element Q1, and the drain of the PMOS transistor is the third terminal of the switching element Q1.

The utility model discloses USB power supply compensation circuit's theory of operation specifically describes as follows:

when an external device is connected through the first USB interface 10 and/or the second USB interface 20, in the first current limiting module 30, the first current limiting chip U1 outputs a USB supply current through its output pin OUT1, and the USB supply current is output to the external device through the first USB interface 10 and/or the second USB interface 20 to provide a driving current for the external device.

In the process that the first current-limiting chip U1 outputs the USB supply current to supply power to the external device, the USB supply current flows through the second resistor R2, and since the USB supply current is consumed by the second resistor R2, a voltage difference is generated on the second resistor R2, namely a voltage V is generated at two ends of the second resistor R2_A、V_BAnd V is_A＞V_B，V_BI.e., the detection voltage outputted from the current detection module 50 to the voltage detection module 60, so that the voltage inputted to the non-inverting input terminal of the comparator U3 is V_B. The utility model discloses regard as the reference with reference voltage Vref of reference voltage input REF input, set in addition under the normal output's of USB supply current the condition, V_B＞Vref。

When the driving current required by the external device connected to the first USB interface 10 and/or the second USB interface 20 does not exceed the maximum USB supply current limited by the first current-limiting chip U1, the USB supply current output by the first current-limiting chip U1 is normally output, and at this time, V is output_BWhen the voltage at the inverting input terminal of the comparator U3 is greater than the voltage at the non-inverting input terminal of the comparator U3, the detection signal output by the output terminal of the comparator U3 is at a low level, and the low-level detection signal is output to the first terminal of the switching element Q1 (i.e. the base of the PNP triode or the gate of the PMOS transistor), and at this time, the first terminal of the switching element Q1 is at a low level, and since the second terminal of the switching element Q1 (i.e. the emitter of the PNP triode or the source of the PMOS transistor) is connected to the power input terminal VIN via the third resistor R3, the second terminal of the switching element Q1 obtains a bias voltage through the third resistor R3, and the second terminal of the switching element Q1 is at a high level, so that the switching element. Since the third terminal of the switching element Q1 (i.e., the collector of the PNP transistor or the drain of the PMOS transistor) is grounded, the enable pin EN2 of the second current-limiting chip U2 is pulled low, the enable pin EN2 of the second current-limiting chip U2 is at a low level, and the second current-limiting chip U2 is at a low level2 is not operated, and the output pin OUT of the second current limiting chip U2 has no compensation current output.

When the driving current required by the external device connected to the first USB interface 10 and/or the second USB interface 20 exceeds the maximum USB supply current limited by the first current limiting chip U1, the USB supply current output from the first current limiting chip U1 to the first USB interface 10 and/or the second USB interface 20 becomes large, that is, the USB supply current flowing through the second resistor R2 becomes large, and at this time, the consumption of the USB supply current on the second resistor R2 becomes large, that is, the voltage on the second resistor R2 becomes large, but because V is a factor of V_AIs not changed, so that the voltage V is detected_BBecome smaller when V_BWhen the voltage is less than Vref, the voltage of the non-inverting input terminal of the comparator U3 is greater than the voltage of the inverting input terminal of the comparator U3, the detection signal output by the output terminal of the comparator U3 is at a high level, the high-level detection signal is output to the first terminal of the switching element Q1 (i.e., the base of the PNP triode or the gate of the PMOS transistor), the first terminal of the switching element Q1 is at a high level, and since the second terminal of the switching element Q1 (i.e., the emitter of the PNP triode or the source of the PMOS transistor) obtains a bias voltage through the third resistor R3, the second terminal of the switching element Q1 is also at a high level, so that the switching element Q1 is turned off. At this time, the enable pin EN2 of the second current-limiting chip U2 obtains a bias voltage through the third resistor R3, the enable pin EN2 of the second current-limiting chip U2 is at a high level, so that the second current-limiting chip U2 is enabled and normally operates, and thus the output pin OUT2 of the second current-limiting chip U2 outputs a compensation current to compensate the USB supply current in time, and the USB supply current output to the external device at this time is a superposition of the USB supply current output by the first current-limiting chip U1 and the compensation current output by the second current-limiting chip U2, so as to reach a driving current required by the external device, thereby satisfying a power supply requirement of the external device, and the external device can normally operate, so that the portable electronic device can read the external device connected thereto.

The utility model discloses still provide a portable electronic equipment, this portable electronic equipment has USB power supply compensating circuit, and above-mentioned embodiment is all referred to this USB power supply compensating circuit's structure, theory of operation and the beneficial effect who brings, and the here is no longer repeated.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings, or directly or indirectly applied to other related technical fields, are included in the same way in the protection scope of the present invention.

Claims

1. A USB power supply compensation circuit is characterized by comprising a power input end, a first USB interface, a second USB interface, a first current limiting module for providing USB power supply current, a second current limiting module for outputting compensation current to compensate the USB power supply current, a current detection module for detecting the USB power supply current and outputting detection voltage according to a detection result, a voltage detection module for detecting the detection voltage and outputting a corresponding detection signal according to the detection result, and a compensation control module for controlling whether the second current limiting module outputs the compensation current or not according to the detection signal; wherein,

2. The USB power compensation circuit of claim 1 wherein the first current limiting module comprises a first current limiting chip, a first resistor, and a first capacitor;

the input pin and the enable pin of the first current limiting chip are both connected with the power supply input end, the current setting pin of the first current limiting chip is grounded through the first resistor, the ground pin of the first current limiting chip is grounded, and the output pin of the first current limiting chip is connected with the input end of the current detection module; one end of the first capacitor is connected with the power input end, and the other end of the first capacitor is grounded.

3. The USB power supply compensation circuit of claim 2, wherein the current detection module includes a second resistor; the first end of the second resistor is connected with the output pin of the first current-limiting chip, and the second end of the second resistor is respectively connected with the power pin of the first USB interface, the power pin of the second USB interface and the input end of the voltage detection module.

4. The USB power compensation circuit of claim 3, wherein the voltage detection module comprises a comparator, a reference voltage input, a first operating voltage input, and a second operating voltage input; the positive power supply end of the comparator is connected with the first working voltage input end, the negative power supply end of the comparator is connected with the second working voltage input end, the in-phase input end of the comparator is connected with the reference voltage input end, the reverse phase input end of the comparator is connected with the second end of the second resistor, and the output end of the comparator is connected with the control end of the compensation control module.

5. The USB power compensation circuit of claim 4, wherein the compensation control module comprises a switching element and a third resistor; the first end of the switch element is connected with the output end of the comparator, the second end of the switch element is connected with the enable end of the second current limiting module and is connected with the power supply input end through the third resistor, and the third end of the switch element is grounded.

6. The USB power compensation circuit as claimed in claim 5, wherein the switching element is a PNP transistor, a base of the PNP transistor is a first terminal of the switching element, an emitter of the PNP transistor is a second terminal of the switching element, and a collector of the PNP transistor is a third terminal of the switching element.

7. The USB power compensation circuit as claimed in claim 5, wherein the switch device is a PMOS transistor, the gate of the PMOS transistor is the first terminal of the switch device, the source of the PMOS transistor is the second terminal of the switch device, and the drain of the PMOS transistor is the third terminal of the switch device.

8. The USB power supply compensation circuit of any one of claims 5 to 7, wherein the second current limiting module comprises a second current limiting chip, a fourth resistor and a second capacitor;

9. A portable electronic device comprising the USB power compensation circuit of any one of claims 1 to 8.