A charging circuit and an adapter

Abstract

A charging circuit comprises a first interface, a control unit, a load switch and a charging unit, wherein the first interface is used for connecting an external power supply; the charging unit is used for connecting an external load, and the external power supply charges the external load through the charging unit; the control unit is electrically connected to the first interface, the load switch and the charging unit, and is used for outputting a first control signal when the external power supply starts and outputting a second control signal when the external power supply stops charging the external load; and the load switch is electrically connected to the first interface, the control unit and the charging unit, and is turned on when the first control signal is received, so that the external power supply charges the external load; and the load switch is turned off when the second control signal is received, so that the voltage is prevented from being backfilled to the first interface through the charging unit, thereby overcoming the defect that the output voltage is backfilled to the input terminal through the charging unit when the external power supply is turned off in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to charging technology, in particular to a charging circuit and an adapter. BACKGROUND

[0002] Charging a super capacitor or a battery with a charging interface such as a USB Type-A interface will cause the output voltage to persist when the power input of the charging interface is turned off due to the extremely low internal resistance of the super capacitor / battery. However, the charging IC usually does not have the function of blocking reverse voltage, so when the power is turned off, the output voltage will be back-primed to the input end through the charging IC, causing the input system to malfunction. SUMMARY

[0003] Therefore, it is necessary to provide a charging circuit that can prevent the output voltage from being back-primed to the input end through the charging IC, causing the input system to malfunction.

[0004] The charging circuit provided by an embodiment of the present application comprises a first interface, a control unit, a load switch and a charging unit, wherein:

[0005] The first interface is used to access an external power supply.

[0006] The charging unit is used to access an external load, and the external power supply charges the external load through the charging unit.

[0007] The control unit is electrically connected to the first interface, the load switch and the charging unit, and is used to output a first control signal when the external power supply is started, and output a second control signal when the external power supply stops charging the external load.

[0008] The load switch is electrically connected to the first interface, the control unit and the charging unit, and is turned on when the first control signal is received, so that the external power supply charges the external load; and is turned off when the second control signal is received, so as to prevent the voltage from being back-primed to the first interface through the charging unit.

[0009] Preferably, the control unit comprises:

[0010] The first resistor is electrically connected to the common end of the first interface and the load switch.

[0011] The second resistor is electrically connected to the other end of the first resistor and grounded.

[0012] The third resistor is electrically connected to the common end of the first resistor and the second resistor, and is electrically connected to the charging unit.

[0013] a fourth resistor, one end of which is electrically connected to the common end of the first interface and the load switch;

[0014] a first electronic switch, comprising a control end, a first end and a second end, the control end being electrically connected to the common end of the first resistor and the second resistor, the first end being electrically connected to the other end of the fourth resistor and the load switch, and the second end being grounded.

[0015] Preferably, the load switch comprises:

[0016] an input end, which is electrically connected to the first interface;

[0017] an enable end, which is electrically connected to the common end of the first electronic switch and the fourth resistor;

[0018] an output end, which is electrically connected to the charging unit.

[0019] Preferably, the charging unit is a charging chip, which comprises:

[0020] an input end, which is electrically connected to the output end of the load switch;

[0021] an LDO output end, which is electrically connected to the other end of the third resistor, and outputs a first voltage signal when the external power supply is started;

[0022] an output end, which is electrically connected to the external load.

[0023] Preferably, when the external power supply charges the external load, a large-capacitance storage charge is formed between the charging unit and the external load.

[0024] Preferably, when the external power supply is started, the LDO output end of the charging unit outputs the first voltage signal to the control end of the first electronic switch through the third resistor, the first electronic switch is turned on, the first control signal is output to the enable end of the load switch, so that the load switch is turned on, and the external power supply charges the external load through the charging chip;

[0025] When the external power supply stops charging, the first voltage signal is 0, the first electronic switch is turned off, and the first electronic switch outputs the second control signal to the enable end of the load switch, so that the load switch is turned off to prevent the voltage of the large-capacitance from back-feeding to the first interface.

[0026] Preferably, when the external power supply is started, the current flowing through the first resistor is the sum of the currents flowing through the second resistor and the third resistor.

[0027] When the external power supply charges the external load, the current flowing through the second resistor is the sum of the currents flowing through the first resistor and the third resistor;

[0028] When the external power source stops charging, the current flowing through the first resistor is the sum of the currents flowing through the second and third resistors.

[0029] To achieve the above objectives, the present invention also provides an adapter comprising the charging circuit described in any of the preceding claims.

[0030] Compared to existing technologies, the charging circuit provided in this invention has a control unit that outputs a first control signal when the external power supply is started, and outputs a second control signal when the external power supply stops charging the external load. When the load switch receives the first control signal, it turns on, and the external power supply charges the external load. When the load switch receives the second control signal, it turns off, thereby preventing voltage from flowing back to the first interface through the charging unit. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a module according to one embodiment of the charging circuit of the present invention.

[0032] Figure 2 This is a circuit diagram of one embodiment of the charging circuit of the present invention.

[0033] Explanation of main component symbols

[0034] Adapter 1

[0035] Charging circuit 10

[0036] External power supply 2

[0037] External load 3

[0038] First interface 100

[0039] Charging unit 101

[0040] Control Unit 102

[0041] Load switch 103

[0042] First resistor - Fourth resistor R1-R4

[0043] Capacitor C

[0044] First electronic switch Q1

[0045] Output terminals Out, Out1

[0046] Input terminals Vin, Vin1

[0047] Enable terminal

[0048] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0049] See Figure 1 As shown, Figure 1 This is a schematic diagram of the adapter 1 of the present invention. The adapter 1 includes a charging circuit 10. The adapter 1 is used to connect to an external power source 2 and an external load 3, so as to charge the external load 3 through the external power source 2. In this embodiment, the charging circuit 10 includes a first interface 100, a charging unit 101, a control unit 102, and a load switch 103.

[0050] In this embodiment, the first interface 100 is used to connect to an external power supply 2. Specifically, the first interface 100 can be, but is not limited to, a USB Type A interface. A charging unit 101 is used to connect to an external load 3, through which the external power supply 2 charges the external load 3. A control unit 102 is electrically connected to the first interface 100, the load switch 103, and the charging unit 101. It outputs a first control signal when the external power supply 2 is started, and outputs a second control signal when the external power supply 2 stops charging the external load 3. The load switch 103 is electrically connected to the first interface 100, the control unit 102, and the charging unit 101. When the first control signal is received, the load switch 103 is turned on, allowing the external power supply 2 to charge the external load 3; when the second control signal is received, the load switch 103 is turned off, preventing voltage from flowing back to the first interface 100 through the charging unit 101. This overcomes the defect in the prior art where, when the external power supply 2 is turned off, the output voltage flows back to the input terminal through the charging unit.

[0051] See Figure 2 As shown, Figure 2This is a circuit diagram of the charging circuit 10 of the present invention. In this embodiment, the control unit 102 includes a first resistor R1, one end of which is electrically connected to the common terminal of the first interface 100 and the load switch 103; a second resistor R2, one end of which is electrically connected to the other end of the first resistor R1, and the other end is grounded; a third resistor R3, one end of which is electrically connected to the common terminal of the first resistor R1 and the second resistor R2, and the other end of which is electrically connected to the charging unit 101; a fourth resistor R4, one end of which is electrically connected to the common terminal of the first interface 100 and the load switch 103; and a first electronic switch Q1, which includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the common terminal of the first resistor R1 and the second resistor R2, the first terminal is electrically connected to the other end of the load switch 103 and the fourth resistor R4, and the second terminal is grounded. In a specific embodiment of the present invention, the first electronic switch Q1 can be an N-type MOS transistor, with its gate electrically connected to the common terminal of the first resistor R1 and the second resistor R2, its drain electrically connected to the other end of the load switch 103 and the fourth resistor R4, and its source grounded.

[0052] In this embodiment, the load switch 103 includes: an input terminal Vin, electrically connected to the first interface 100; an enable terminal Enable, electrically connected to the common terminal of the first electronic switch Q1 and the fourth resistor R4, wherein the enable terminal is active at a low level, and when the enable terminal receives a low level signal, the load switch is turned on, and when the enable terminal receives a high level signal, the load switch is turned off; and an output terminal Vout, electrically connected to the charging unit 101.

[0053] In this embodiment, the charging unit 101 is a charging chip, which includes: an input terminal Vin1, electrically connected to the output terminal of the load switch 103; an LDO output terminal, electrically connected to the other end of the third resistor R3, which outputs a first voltage signal when the external power supply 2 is started; and an output terminal Vout1, electrically connected to the external load 3.

[0054] Specifically, when the external power supply 2 charges the external load 3, a large capacitor C is formed between the charging unit 101 and the external load 3 to store charge, that is, a large capacitor is formed between the output terminal of the charging chip and the external load 3. When the external power supply 2 is turned on, the LDO output terminal of the charging unit 101 outputs the first voltage signal to the control terminal of the first electronic switch Q1 through the third resistor R3. The first electronic switch Q1 is turned on, and outputs the first control signal to the enable terminal of the load switch 103, so that the load switch 103 is turned on, and the external power supply 2 charges the external load 3 through the charging chip. When the external power supply 2 stops charging, the first voltage signal becomes 0, the first electronic switch Q1 is turned off, and the first electronic switch Q1 outputs the second control signal to the enable terminal of the load switch 103, so that the load switch 103 is turned off, to prevent the voltage of the large capacitor from flowing back to the first interface, thereby overcoming the defect in the prior art that when the external power supply 2 is turned off, the output voltage will flow back to the input terminal through the charging unit.

[0055] In this embodiment, when the external power supply 2 is started, the current flowing through the first resistor R1 is the sum of the currents flowing through the second resistor R2 and the third resistor R3;

[0056] When the external power supply 2 charges the external load 3, the current flowing through the second resistor R2 is the sum of the currents flowing through the first resistor R1 and the third resistor R3;

[0057] When the external power supply 2 stops charging, the current flowing through the first resistor R1 is the sum of the currents flowing through the second resistor R2 and the third resistor R3.

[0058] Compared to existing technologies, the charging circuit provided in this invention has a control unit that outputs a first control signal when the external power supply is started, and outputs a second control signal when the external power supply stops charging the external load. The load switch then turns on when it receives the first control signal, allowing the external power supply to charge the external load. The load switch turns off when it receives the second control signal, thereby preventing voltage from flowing back to the first interface through the charging unit.

[0059] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any appropriate changes and modifications made to the above embodiments within the essential spirit and scope of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A charging circuit, characterized in that, include: The first interface is used to connect an external power source; The charging unit is a charging chip used to connect to an external load, and the external power supply charges the external load through the charging unit. The control unit is electrically connected to the first interface and the charging unit, and is used to output a first control signal when the external power supply is started, and to output a second control signal when the external power supply stops charging the external load. A load switch is electrically connected to the first interface, the control unit, and the charging unit. When the first control signal is received, the load switch is turned on, and the external power supply charges the external load. When the second control signal is received, the load switch is turned off to prevent voltage from flowing back to the first interface through the charging unit. The control unit includes: The first resistor has one end electrically connected to the common terminal of the first interface and the load switch; The second resistor has one end electrically connected to the other end of the first resistor, and the other end grounded. The third resistor has one end electrically connected to the common terminal of the first resistor and the second resistor, and the other end electrically connected to the charging unit; The fourth resistor has one end electrically connected to the common terminal of the first interface and the load switch; A first electronic switch includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the common terminal of the first resistor and the second resistor. The first terminal is electrically connected to the other end of the load switch and the fourth resistor. The second terminal is grounded. When the external power supply is started, the LDO output terminal of the charging unit outputs a first voltage signal to the control terminal of the first electronic switch through the third resistor. The first electronic switch is turned on and outputs the first control signal to the enable terminal of the load switch, so that the load switch is turned on. The external power supply charges the external load through the charging chip. When the external power supply charges the external load, a large capacitor is formed between the charging unit and the external load to store charge. When the external power supply stops charging, the first voltage signal is 0, the first electronic switch is turned off, and the first electronic switch outputs the second control signal to the enable terminal of the load switch, causing the load switch to disconnect to prevent the voltage of the large capacitor from flowing back to the first interface.

2. The charging circuit as described in claim 1, characterized in that, The load switch includes: The input terminal is electrically connected to the first interface; The enabling terminal is electrically connected to the common terminal of the first electronic switch and the fourth resistor; The output terminal is electrically connected to the charging unit.

3. The charging circuit as described in claim 2, characterized in that, The charging chip includes: The input terminal is electrically connected to the output terminal of the load switch; The LDO output terminal is electrically connected to the other end of the third resistor. When the external power supply is started, the LDO output terminal outputs a first voltage signal. The output terminal is electrically connected to the external load.

4. The charging circuit as described in claim 1, characterized in that: When the external power supply is started, the current flowing through the first resistor is the sum of the currents flowing through the second and third resistors; When the external power supply charges the external load, the current flowing through the second resistor is the sum of the currents flowing through the first resistor and the third resistor; When the external power source stops charging, the current flowing through the first resistor is the sum of the currents flowing through the second and third resistors.

5. An adapter, characterized in that, It includes the charging circuit as described in any one of claims 1 to 4.

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