Power supply control circuit

Abstract

The utility model relates to a power supply control circuit which comprises a power supply management chip, an input filter circuit, a transformer circuit, an output rectification filter circuit, a power supply circuit, a photoelectric isolation feedback circuit, a thermistor circuit, a photoelectric isolation circuit and a control signal input circuit. The input filter circuit is connected with a power input end and is sequentially connected with the transformer circuit, the output filter circuit and a power output end; a first control port of the power management chip is connected with the thermistor circuit and the photoelectric isolation circuit; a third control port and a fifth control port of the power management chip are connected with a transformer circuit; a sixth control port of the power management chip is connected with the power supply circuit; an eighth control port of the power management chip is connected with the input filter circuit; the control signal input circuit is connected with the optoelectronic isolation feedback circuit; the optoelectronic isolation feedback circuit is connected with the output rectification filter circuit. The scheme simplifies the circuit structure and improves the power supply control stability.

Description

Technical Field

[0001] This utility model relates to the field of signal processing technology, specifically to a power control circuit. Background Technology

[0002] In some electrical devices, such as skin rejuvenation devices and hair removal devices, power control typically includes a main high-voltage power supply circuit, a main power output control circuit, and an auxiliary power supply circuit. The main high-voltage power supply circuit is usually controlled by a separate auxiliary power supply circuit. The auxiliary power supply outputs approximately 15V DC, which is supplied to the main power supply chip's power pin via an external control signal, controlling the main power supply's on / off state. However, this power control circuit adds an auxiliary power supply circuit, increasing circuit complexity and cost. Furthermore, if a short circuit occurs during main power supply operation, the supply voltage to the power management chip in the main high-voltage power supply circuit will not decrease, thus failing to provide short-circuit protection and resulting in low reliability of the power control circuit.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This invention provides a power control circuit that can effectively overcome the defects existing in the prior art.

[0005] Other features and advantages of this invention will become apparent from the following detailed description, or may be learned in part by practice of this disclosure.

[0006] According to a first aspect of the present invention, a power control circuit is provided, comprising: a power management chip, an input filter circuit, a transformer circuit, an output rectifier filter circuit, a power supply circuit, an opto-isolation feedback circuit, a thermistor circuit, an opto-isolation circuit, and a control signal input circuit.

[0007] The input filter circuit is connected to the power input terminal and sequentially connected to the transformer circuit, the output filter circuit, and the power output terminal; the first control port of the power management chip is connected to the thermistor circuit and the opto-isolation circuit; the third and fifth control ports of the power management chip are connected to the transformer circuit; the sixth control port of the power management chip is connected to the power supply circuit; and the eighth control port of the power management chip is connected to the input filter circuit.

[0008] The control signal input circuit is connected to the opto-isolation feedback circuit; the opto-isolation feedback circuit is connected to the output rectifier and filter circuit.

[0009] In some exemplary embodiments, the input filtering circuit includes an EMC filtering circuit and a rectifier filtering circuit connected in sequence; wherein the EMC filtering circuit is connected to the power input terminal; and the rectifier filtering circuit is connected to the input terminal of the transformer circuit.

[0010] In some exemplary embodiments, the transformer circuit is connected to the power supply circuit.

[0011] In some exemplary embodiments, the transformer circuit includes a power switch and a high-frequency isolation transformer circuit.

[0012] In some exemplary embodiments, when the control signal input circuit receives a low-level signal, the power management chip executes an over-temperature protection mode; when the control signal input circuit receives a high-level signal, the power management chip exits the over-temperature protection mode.

[0013] The power control circuit provided in this embodiment of the invention incorporates a power management chip. The first control port of the power management chip is connected to a thermistor circuit and an opto-isolation circuit; the third and fifth control ports are connected to a transformer circuit; the sixth control port is connected to a power supply circuit; the eighth control port is connected to an input filter circuit; and the control signal input circuit is connected to an opto-isolation feedback circuit. The main power output start / stop control is achieved through the over-temperature protection pin of the power management chip. When the external control signal input circuit outputs a low-level signal, the power management chip enters over-temperature protection, the power supply does not work, and there is no output voltage. When the control signal input circuit outputs a high-level signal, the power management chip exits over-temperature protection, the power supply outputs normally, and the main power supply start / stop control is achieved. This simplifies the circuit structure and improves the stability of power control.

[0014] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] Figure 1 This diagram schematically illustrates the module composition of a power control circuit in an exemplary embodiment of the present invention.

[0017] Figure 2The schematic diagram illustrates a power control circuit in an exemplary embodiment of the present invention.

[0018] Figure 3 The schematic diagram illustrates a control signal input circuit of an exemplary embodiment of the present invention. Detailed Implementation

[0019] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0020] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted.

[0021] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be understood that in the disclosure of the present invention, the terms “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention. Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," and "coupling," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art should be able to understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] To address the shortcomings and deficiencies of existing technologies, this exemplary embodiment provides a power control circuit that can be used in beauty electrical appliances and implements an isolated control power supply for starting and stopping the electrical appliances. (Reference) Figure 1As shown, the power control circuit includes: input terminal 11, input filter circuit 12, transformer circuit 13, output rectifier filter circuit 14, opto-isolation feedback circuit 15, power management chip 16, power supply circuit 17, thermistor circuit 18, opto-isolation circuit 19, control signal input circuit 20, and output terminal. The input filter circuit 12 includes an EMC filter (electromagnetic compatibility filter) circuit 121 and a rectifier filter circuit 122. The transformer circuit 13 includes a power switching transistor and a high-frequency isolation transformer circuit.

[0023] Specifically, input terminal 11 can be connected to the power supply terminal, and then sequentially connected to EMC filter circuit 121, rectifier filter circuit 122, transformer circuit 13, output filter circuit 14, and output terminal 21. Power control chip 16 is connected to power supply circuit 17, thermistor 18, opto-isolation circuit 19, and opto-isolation feedback circuit 15; opto-isolation circuit 19 is connected to control signal input circuit 20.

[0024] For example, the power management chip can be an LD7750EGR chip.

[0025] For example, refer to Figure 2 As shown, the thermistor circuit may include a resistor R35 and a thermistor RE2 connected in series. One end of resistor R35 is connected to the first control port (RT) of the power management chip U1, and the other end is connected to the thermistor RE2. The other end of the thermistor RE2 is connected to the ground terminal PGND.

[0026] The opto-isolation circuit includes an optocoupler U8B. Terminal 4 of optocoupler U8B is connected to the first control port (RT) of the power management chip U1, and terminal 3 of optocoupler U8B is connected to the ground terminal PGND. Optocoupler U8B and the thermistor circuit are connected in parallel.

[0027] For example, the second control port (COMP) of the power management chip U1 is connected to the first end of capacitor C13 and the first end of resistor R36. The second end of capacitor C13 is connected to the third end of optocoupler U8B and the ground terminal PGND. The second end of resistor R36 is connected to the first end of resistor R43, the first end of resistor R44, and the fourth port of optocoupler U2B. The second ends of resistor R43, the second ends of resistor R44, and the third port of optocoupler U2B are connected to the ground terminal PGND.

[0028] For example, refer to Figure 3As shown, the control signal input circuit includes: optocoupler U8A, resistors R51, R52, and R53, and transistor Q4. The first terminal of resistor R52 is connected to the signal input terminal to receive the crt_en signal; the second terminal of resistor R52 is connected to the first terminal of resistor R51 and the base of transistor Q4; the second terminal of resistor R51 is connected to the emitter of transistor Q4, the second port of optocoupler UBA, and the ground terminal SGND; the collector of transistor Q4 is connected to the first port of optocoupler UBA and the second terminal of resistor R53; the first terminal of resistor R53 is connected to the +12V power supply.

[0029] For example, the third control port (CS) of the power management chip U1 is connected to the first end of capacitor C16 and the first end of resistor R42; the second end of capacitor C16 is connected to the ground terminal PGND; and the second end of resistor R42 is connected to the second end of resistor R39 in the power switch and high-frequency isolation transformer circuit.

[0030] For example, the fifth control port (DUT) of the power management chip U1 is connected to the first end of resistor R37, and the second end of resistor R37 is connected to the first end of resistor R32 and the base of transistor Q2; the second end of resistor R32 is connected to the collector of transistor Q2, the power switch, and the first end of the switching device Q1 in the high-frequency isolation transformer circuit. The structures of the output rectifier filter circuit, the power switch and high-frequency isolation transformer, and the opto-isolation feedback circuit are as follows: Figure 2 As shown. Of course, other circuit structures with the same function may also be used in other exemplary embodiments of this disclosure.

[0031] For example, the power supply circuit includes capacitor C11 and diode D7. The first terminal of capacitor C11 is connected to the sixth control port of power management chip U1 and the negative terminal of diode D7; the second terminal of capacitor C11 is connected to ground GND. The positive terminal of diode D7 is connected to the PU terminal in the power switching transistor and high-frequency isolation transformer circuit.

[0032] For example, the structures of EMC filter circuits and rectifier filter circuits are as follows: Figure 2 As shown. The EMC filter circuit and the rectifier filter circuit are connected in series; the eighth control port (HV) of the power management chip U1 is connected to the output terminals of the EMC filter circuit in series with resistors R30 and R26, and diodes D5 and D6 are respectively installed.

[0033] Specifically, pin 1 of the power management chip U1 is the over-temperature protection pin. When the crt_en signal in the external control signal input circuit is low, the LED of optocoupler U8A and optocoupler U8B are turned on, the power management chip enters over-temperature protection, the power supply does not work, and there is no output voltage. When the crt_en signal in the external control circuit is high, the LED of optocoupler U8A and optocoupler U8B are turned off, the power management chip exits over-temperature protection, and the power supply outputs normally. The main power supply start / stop control is achieved through the over-temperature protection pin 1 of the power management chip U1. Under normal operating conditions, the power supply is rectified by D5 and D6, and then current-limited by resistors R26 and R30 before being connected to the HV start pin of the power management chip. After the chip starts up, it is powered by the auxiliary winding of the transformer. The auxiliary winding of the transformer is current-limited by resistor R25, rectified by diode D7, filtered by electrolytic capacitor C11, and then connected to the VCC pin 6 of the power management chip. When a short circuit occurs in the power output during normal operation, the output voltage drops, which in turn lowers the VCC voltage of the auxiliary winding, causing the power management chip to enter the VCC undervoltage protection mode.

[0034] The power control circuit of this invention controls the power management chip to switch between over-temperature protection states based on the high / low level changes of the crt_en signal in the control signal input circuit, thereby controlling the power output. Based on this circuit structure and control method, the auxiliary power supply circuit is eliminated, the circuit structure is simplified, and the reliability and stability of power control are improved.

[0035] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0036] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A power supply control circuit, characterized in that, The power control circuit includes: a power management chip, an input filter circuit, a transformer circuit, an output rectifier filter circuit, a power supply circuit, an opto-isolation feedback circuit, a thermistor circuit, an opto-isolation circuit, and a control signal input circuit; the input filter circuit is connected to the power input terminal and is connected in sequence to the transformer circuit, the output filter circuit, and the power output terminal. The first control port of the power management chip is connected to the thermistor circuit and the opto-isolation circuit; the third and fifth control ports of the power management chip are connected to the transformer circuit; the sixth control port of the power management chip is connected to the power supply circuit; and the eighth control port of the power management chip is connected to the input filter circuit. The control signal input circuit is connected to the opto-isolation feedback circuit; the opto-isolation feedback circuit is connected to the output rectifier and filter circuit.

2. The power control circuit according to claim 1, characterized in that, The input filtering circuit includes an EMC filtering circuit and a rectifier filtering circuit connected in sequence; wherein, the EMC filtering circuit is connected to the power input terminal; and the rectifier filtering circuit is connected to the input terminal of the transformer circuit.

3. The power control circuit according to claim 1, characterized in that, The transformer circuit is connected to the power supply circuit.

4. The power control circuit according to claim 1 or 3, characterized in that, The transformer circuit includes a power switching transistor and a high-frequency isolation transformer circuit.

5. The power control circuit according to claim 1, characterized in that, When the control signal input circuit receives a low-level signal, the power management chip executes the over-temperature protection mode; when the control signal input circuit receives a high-level signal, the power management chip exits the over-temperature protection mode.

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