Digital display multi-gear switching power supply with independent keys

Abstract

The utility model relates to the technical field of electric appliances, in particular to an independent key digital display multi-gear switching power supply, which comprises an MCU (Microprogrammed Control Unit), a switching circuit connected with the MCU, a voltage selection key K1 and a nixie tube, the switching circuit comprises a power plug P2, an alternating current rectifier bridge BZ1, a transformer BK1, a Schottky diode D1, a chip U2, an optocoupler U1B, an MOS (Metal Oxide Semiconductor) tube Q1, a rectification filter capacitor C5, an optocoupler U1A and a triode Q3, the power plug P2 is connected with the alternating current rectifier bridge BZ1, the voltage selection key K1 is connected with the voltage selection key K1, and the nixie tube is connected with the voltage selection key K1. The alternating current rectifier bridge BZ1 is connected with a transformer BK1, a Schottky diode D1 and a chip U2, and the chip U2 is connected with an optocoupler U1B, a triode Q3, an optocoupler U1A and a rectifier filter capacitor C5; according to the multi-gear switching power supply of the utility model, the touch switch is used as a switching power supply for selecting a plurality of voltage outputs for voltage regulation; the application that one output winding outputs a plurality of different voltages and one touch switch selects a plurality of different output voltages is achieved, the function of memorizing the last working state is achieved, the same electric appliance is used, and voltage does not need to be selected again.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, and in particular to a multi-level switching power supply with independent buttons and digital display. Background Technology

[0002] Currently available adjustable switching power supplies are bulky and use transformers with industrial frequency iron cores and multiple taps, or high-frequency magnetic core transformers, making it difficult to achieve precise control of multiple voltage outputs simultaneously. The maximum operating voltage of the chips on the AC control side of the switching power supply is limited, making it incompatible with multiple voltages. Low-voltage outputs are easily controlled; however, when high-voltage outputs are required, the chip's power supply will trigger overvoltage protection. Furthermore, the selected output voltage is not displayed, making the selection unintuitive and prone to errors during use. The same receiver requires voltage readjustment each time it is used, as it cannot retain memory and cannot meet the needs of different voltage applications on the market. Summary of the Invention

[0003] The purpose of this invention is to provide an independent button digital display multi-level switching power supply to solve the technical problem that existing switching power supplies require readjustment of the selected voltage every time they are used and cannot retain the memory function.

[0004] This utility model discloses an independent button digital display multi-level switching power supply, including an MCU, a switching circuit connected to the MCU, a voltage selection button K1, and a digital display.

[0005] The switching circuit includes a power plug P2, an AC rectifier bridge BZ1, a transformer BK1, a Schottky diode D1, a chip U2, an optocoupler U1B, a MOSFET Q1, a rectifier filter capacitor C5, an optocoupler U1A, and a transistor Q3. The power plug P2 is connected to the AC rectifier bridge BZ1, which is connected to the transformer BK1, the Schottky diode D1, and the chip U2. The chip U2 is connected to the optocoupler U1B, the transistor Q3, the optocoupler U1A, and the rectifier filter capacitor C5.

[0006] A peak absorption circuit is connected to pin 3 of the transformer BK1, and a resistor R7, a diode D10, and the VCC terminal are connected to pin 5. A voltage regulator circuit is connected to the VCC terminal, and the VDD terminal of the voltage regulator circuit is connected to the VDD terminal of chip U2. Capacitors C4 and C8 are also connected to the VDD terminal of chip U2. The input terminal of capacitor C4 is connected to AC rectifier bridge BZ1. Pin 3 of chip U2 is connected to the input terminal of optocoupler U1B. Pin 6 of chip U2 is connected to the gate of MOSFET Q1. The drain of MOSFET Q1 is connected to pin 3 of transformer BK1, and the source of MOSFET Q1 is connected to resistors R20, R21, R22, and R23.

[0007] A protection circuit is connected to the Schottky diode D1. The output terminal of the Schottky diode D1 is connected to the rectifier filter capacitor C5. The rectifier filter capacitor C5 is connected to the optocoupler U1A and the transistor Q3. The two ends of the optocoupler U1A are connected to an optocoupler compensation circuit. The optocoupler compensation circuit is also connected to an upper voltage divider resistor R6 and a lower voltage divider resistor R25. The connection point of the upper voltage divider resistor R6 and the lower voltage divider resistor R25 is the voltage divider point ADJ. The voltage divider point ADJ is connected to the common network node of the MCU multi-level voltage control resistor.

[0008] Preferably, a thermistor RT1 is also connected between the power plug P2 and the AC rectifier bridge BZ1.

[0009] Preferably, the peak absorption circuit includes a resistor R3, a capacitor C2, and a diode D2 to absorb peak values; the protection circuit includes a resistor R9 and a capacitor C6 to protect the Schottky diode D1 from breakdown; the voltage regulator circuit includes a transistor Q2, a resistor R16, a Zener diode WD1, and a capacitor C13; and the optocoupler compensation circuit includes a resistor R10, a resistor R12, a capacitor C7, and a capacitor C9.

[0010] Preferably, the VDD terminal of the chip U2 is branched and connected to resistors R2, R5 and R8, one end of resistor R8 is connected to capacitor C8, and one end of resistor R2 is connected to AC rectifier bridge BZ1.

[0011] Preferably, the optocoupler U1B is the high-voltage end, and the optocoupler U1A is the low-voltage end.

[0012] Preferably, a resistor R14 and a resistor R24 ​​are connected between pin 6 of the chip U2 and the gate of the MOS transistor Q1, and a capacitor C12 and a resistor R18 are connected between pin 4 of the chip U2 and the source of the MOS transistor Q1.

[0013] Preferably, the display driver chip of the digital tube is 74HC595.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] This independent button digital display multi-level switching power supply uses a single tactile switch as a voltage regulator to select multiple output voltages. It combines the output DC reference sampling circuit of the switching power supply with the control input switch quantity, PWM duty cycle, current protection control, voltage protection regulation, and MCU intelligent control, demonstrating the integration of microcontroller control and power supply control. This enables the application of multiple different voltages output from a single output winding and multiple different output voltages selectable by a single tactile switch. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0017] Figure 1 This is a switching circuit diagram of an independent button digital display multi-level switching power supply according to this utility model;

[0018] Figure 2 This is a circuit diagram of an independent button digital display multi-level switching power supply MCU, voltage selection button K1, and digital tube.

[0019] Figure 3 This is a schematic diagram illustrating the usage steps of an independent button digital display multi-level switching power supply according to this utility model. Detailed Implementation

[0020] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0021] like Figure 1-3 As shown, this utility model discloses an independent button digital display multi-level switching power supply, including an MCU, a switching circuit connected to the MCU, a voltage selection button K1, and a digital tube. The display driver chip of the digital tube is 74HC595.

[0022] The switching circuit includes a power plug P2, an AC rectifier bridge BZ1, a transformer BK1, a Schottky diode D1, a chip U2, an optocoupler U1B, a MOSFET Q1, a rectifier filter capacitor C5, an optocoupler U1A, and a transistor Q3. The power plug P2 is connected to the AC rectifier bridge BZ1. The AC rectifier bridge BZ1 is connected to the transformer BK1, the Schottky diode D1, and the chip U2. The chip U2 is connected to the optocoupler U1B, the transistor Q3, the optocoupler U1A, and the rectifier filter capacitor C5.

[0023] A peak absorption circuit is connected to pin 3 of transformer BK1, and resistor R7, diode D10, and VCC are connected to pin 5. A voltage regulator circuit is connected to the VCC terminal. The VDD terminal of the voltage regulator circuit is connected to the VDD terminal of chip U2. Capacitors C4 and C8 are also connected to the VDD terminal of chip U2. The input terminal of capacitor C4 is connected to AC rectifier bridge BZ1. Pin 3 of chip U2 is connected to the input terminal of optocoupler U1B. Pin 6 of chip U2 is connected to the gate of MOSFET Q1. The drain of MOSFET Q1 is connected to pin 3 of transformer BK1. The source of MOSFET Q1 is connected to resistors R20, R21, R22, and R23.

[0024] A protection circuit is connected to Schottky diode D1. The output terminal of Schottky diode D1 is connected to rectifier filter capacitor C5. Rectifier filter capacitor C5 is connected to optocoupler U1A and transistor Q3. Optocoupler U1A is connected to an optocoupler compensation circuit. The optocoupler compensation circuit is also connected to upper voltage divider resistor R6 and lower voltage divider resistor R25. The connection point of upper voltage divider resistor R6 and lower voltage divider resistor R25 is the voltage divider point ADJ. The voltage divider point ADJ is connected to the common network node of the MCU multi-level voltage control resistor.

[0025] This utility model relates to an independent button digital display multi-level power supply, mainly comprising an MCU, a switching circuit connected to the MCU, a voltage selection button K1, and a digital tube. The MCU controls the switching circuit, and the voltage selection button K1 is a voltage selection tactile switch. The switch is normally open; pressing it connects the power supply, and releasing it disconnects it. Additionally, see reference... Figure 2 The MCU's VCC power supply comes from the VCC terminal of the MCU's voltage regulator circuit. The MCU is also connected to the display driver chip. The display driver signals SHCP, DS, and STCP are connected to the corresponding network nodes of the MCU, while A, B, C, D, E, F, and G are directly connected to the corresponding network nodes of the digital tube. P3 is the MCU program burning communication interface. The MCU can be any model. The MCU's voltage regulator power supply is provided through U3, and the U3 model is L7805.

[0026] The switching circuit of this multi-range switching power supply includes a power plug P2, an AC rectifier bridge BZ1, a transformer BK1, a Schottky diode D1, a chip U2, an optocoupler U1B, a MOSFET Q1, a rectifier filter capacitor C5, an optocoupler U1A, and a transistor Q3. The power plug P2 is an AC power plug. A thermistor RT1 is connected between the power plug P2 and the AC rectifier bridge BZ1. The thermistor RT1 limits the current surge when the power is turned on, protecting the power plug. A peak absorption circuit is connected to the transformer BK1 to reduce losses during current and voltage conversion, while also protecting the transformer BK1.

[0027] In the switching circuit, the resistor R7, diode D10, and power supply VCC connected to pin 5 of transformer BK1 are regulated by a voltage regulator circuit, namely transistor Q2, R16, Zener diode DW1, and capacitor C13. The voltage is then connected from the VDD terminal to the VDD terminal of chip U2 for startup power supply. The VDD terminal of chip U2 is also connected to resistors R2, R5, and R8. After being filtered by capacitor C8, a weak current is provided to chip U2 as a startup current. After startup, a stable operating voltage is provided to chip U2 by the secondary voltage regulator to maintain operation.

[0028] In the switching circuit, MOSFET Q1 is controlled by the current-limiting resistors R14 and R24 connected externally to chip U2. The drain of MOSFET Q1 is connected to pin 3 (MOS_D) of transformer BK1. The source of MOSFET Q1 is connected to the front-end rectified output ground line via R20, R21, R22, and R23, and simultaneously filtered by R18 and C12 to the current detection pin of chip U2 for power control and overcurrent protection. Pins 10 and 12 of the secondary winding of transformer BK1 are connected to synchronous rectification or Schottky diode D1 for rectification. The circuit protection circuit on Schottky diode D1, namely resistor R9 and capacitor C6, acts as peak absorption to protect Schottky diode D1 from breakdown. The capacitor C5 connected to pin 2 of Schottky diode D1 is the rectifier filter capacitor. The output is current-limited to the low-voltage side of optocoupler via resistor R4. Optocoupler U1A controls optocoupler U1B, where optocoupler U1B is the high-voltage side and optocoupler U1A is the low-voltage side.

[0029] In a preferred embodiment, refer to Figure 1 The peak absorption circuit of the switching power supply includes a resistor R3, a capacitor C2, and a diode D2 to absorb peak values; the protection circuit includes a resistor R9 and a capacitor C6 to protect the Schottky diode D1 from breakdown; the voltage regulation circuit includes a transistor Q2, a resistor R16, a Zener diode WD1, and a capacitor C13; and the optocoupler compensation circuit includes a resistor R10, a resistor R12, a capacitor C7, and a capacitor C9.

[0030] In a preferred embodiment, refer to Figure 1 In this switching power supply, the VDD terminal of chip U2 is branched with resistors R2, R5, and R8. One end of resistor R8 is connected to capacitor C8, and one end of resistor R2 is connected to the AC rectifier bridge BZ1. Resistors R14 and R24 are also connected between pin 6 of chip U2 and the gate of MOSFET Q1, and capacitor C12 and resistor R18 are connected between pin 4 of chip U2 and the source of MOSFET Q1. Chip U2 is a PWM chip.

[0031] This switching power supply utilizes a single tactile switch as a voltage regulator to select multiple output voltages. It combines the output DC reference sampling circuit of the switching power supply with the control input switch quantity, PWM duty cycle, current protection control, voltage protection regulation technology, and MCU intelligent control technology, demonstrating the integration of microcontroller technology and power control technology. This enables the application of multiple different voltages output from a single output winding and multiple different output voltages selectable by a single tactile switch.

[0032] This switching power supply features a single tactile switch that allows for multiple voltage selections: 10 or more voltage levels, such as 5V, 9V, 12V, 15V, 16V, 18V, 19V, 20V, 22V, and 24V, to meet the needs of different voltage products on the market. The power output is determined by the power supply's requirements. Different voltage outputs are selected cyclically by a single tactile switch, and the output is locked after 10 seconds to prevent accidental operation and damage to the equipment. The power supply remembers the last operating state and retains the previously selected output voltage, simplifying the operation process. If used with the same appliance, it can be used permanently without adjustment.

[0033] The power supply uses a two-stage voltage regulation system for the front-end chip, and the feedback reference voltage regulation in the later stage is matched by multiple ports of the MCU; it is combined with a tactile switch and a digital tube to display and control multiple voltage outputs.

[0034] The MCU port has four functions: standard bidirectional port (input and output), push-pull output port, high-impedance input port, and open-drain output port.

[0035] The tactile switch is connected to one of the standard bidirectional ports of the MCU as a voltage selection port. Each press of the tactile switch increases the selected voltage from small to large. When the maximum voltage level is reached, the voltage level decreases to the minimum voltage level. This cycle continues until a satisfactory output voltage level is selected.

[0036] The default output minimum voltage is used for the first time. When used again, the output voltage is remembered based on the previous use and will remain at the previous value until a new value is manually selected. Otherwise, it will remain unchanged indefinitely.

[0037] If the device is powered on for 10 seconds or the button is not pressed again for 10 seconds, the current selection value will be locked and memorized until the power is turned on again and the selection is made again; otherwise, the previously locked value will remain unchanged.

[0038] Digital tube display: The minimum value is displayed on the first use. Within 10 seconds of power-on, the button can be used to select, and the digital tube will display the current value accordingly. After 10 seconds, it will be locked and the button will be disabled to prevent accidental operation during use.

[0039] The switching power supply transformer is a conventional single-output winding, and the switching power supply chip can be any switching power supply chip, with secondary voltage regulation in the chip's power supply. The DC reference output of the switching power supply is a precision reference chip such as TL431 or TL432. The pull-up resistor of the reference chip is a fixed precision resistor, and the non-grounded terminal of the pull-down precision resistor is connected to four MCU ports with standard bidirectional ports (input and output), push-pull output ports, high-impedance input ports, and open-drain output ports, respectively, through their respective series resistors. The four functions within the MCU connect to the chip's power supply terminal or ground terminal as needed, achieving the purpose of regulating and stabilizing different voltages. Alternatively, an MCU with DAC function can be connected to the input terminal of the reference power supply (with the pull-up and pull-down resistors connected to the reference input terminal), and the MCU adjusts the reference voltage according to the voltage selected by the tactile switch to control the output voltage.

[0040] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A multi-level switching power supply with independent button and digital display, characterized in that: This includes an MCU, a switching circuit connected to the MCU, a voltage selection button K1, and a digital display. The switching circuit includes a power plug P2, an AC rectifier bridge BZ1, a transformer BK1, a Schottky diode D1, a chip U2, an optocoupler U1B, a MOSFET Q1, a rectifier filter capacitor C5, an optocoupler U1A, and a transistor Q3. The power plug P2 is connected to the AC rectifier bridge BZ1, which is connected to the transformer BK1, the Schottky diode D1, and the chip U2. The chip U2 is connected to the optocoupler U1B, the transistor Q3, the optocoupler U1A, and the rectifier filter capacitor C5. A peak absorption circuit is connected to pin 3 of the transformer BK1, and a resistor R7, a diode D10, and the VCC terminal are connected to pin 5. A voltage regulator circuit is connected to the VCC terminal, and the VDD terminal of the voltage regulator circuit is connected to the VDD terminal of chip U2. Capacitors C4 and C8 are also connected to the VDD terminal of chip U2. The input terminal of capacitor C4 is connected to AC rectifier bridge BZ1. Pin 3 of chip U2 is connected to the input terminal of optocoupler U1 B. Pin 6 of chip U2 is connected to the gate of MOSFET Q1. The drain of MOSFET Q1 is connected to pin 3 of transformer BK1, and the source of MOSFET Q1 is connected to resistors R20, R21, R22, and R23. A protection circuit is connected to the Schottky diode D1. The output terminal of the Schottky diode D1 is connected to the rectifier filter capacitor C5. The rectifier filter capacitor C5 is connected to the optocoupler U1A and the transistor Q3. The two ends of the optocoupler U1A are connected to an optocoupler compensation circuit. The optocoupler compensation circuit is also connected to an upper voltage divider resistor R6 and a lower voltage divider resistor R25. The connection point of the upper voltage divider resistor R6 and the lower voltage divider resistor R25 is the voltage divider point ADJ. The voltage divider point ADJ is connected to the common network node of the MCU multi-level voltage control resistor.

2. The independent button digital display multi-level switching power supply as described in claim 1, characterized in that, A thermistor RT1 is also connected between the power plug P2 and the AC rectifier bridge BZ1.

3. The independent button digital display multi-level switching power supply as described in claim 1, characterized in that, The peak absorption circuit includes a resistor R3, a capacitor C2, and a diode D2 to absorb peak values; the protection circuit includes a resistor R9 and a capacitor C6 to protect the Schottky diode D1 from breakdown; the voltage regulator circuit includes a transistor Q2, a resistor R16, a Zener diode WD1, and a capacitor C13; the optocoupler compensation circuit includes a resistor R10, a resistor R12, a capacitor C7, and a capacitor C9.

4. The independent button digital display multi-level switching power supply as described in claim 1, characterized in that, The VDD terminal of the chip U2 is branched and connected to resistors R2, R5 and R8. One end of resistor R8 is connected to capacitor C8, and one end of resistor R2 is connected to AC rectifier bridge BZ1.

5. The independent button digital display multi-level switching power supply as described in claim 1, characterized in that, The optocoupler U1B is the high-voltage end, and the optocoupler U1A is the low-voltage end.

6. The independent button digital display multi-level switching power supply as described in claim 1, characterized in that, Resistors R14 and R24 are connected between pin 6 of chip U2 and the gate of MOSFET Q1, and capacitor C12 and resistor R18 are connected between pin 4 of chip U2 and the source of MOSFET Q1.

7. The independent button digital display multi-level switching power supply as described in claim 1, characterized in that, The display driver chip for the digital tube is 74HC595.

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