Switching power supply

Abstract

The utility model discloses a switching power supply. The switching power supply comprises a power supply input module, a power supply access module, a power supply management controller, a voltage conversion module, an auxiliary power supply module and a switch, wherein the power supply management controller comprises a control pin; the power supply unit is used for acquiring the power supply voltage from the power supply input module through the power supply access module in a shutdown state and acquiring the power supply voltage from the auxiliary power supply module and the power supply access module in a working state, and carrying out voltage processing; the detection unit is used for receiving an operation signal of the switch and determining a current state; and the control unit is used for allowing the driving voltage conversion module to carry out conversion processing in the working state and stopping the conversion processing in the shutdown state. According to the technical scheme, in the shutdown state (that is, power does not need to be supplied to the secondary load), under the condition that power consumption is not additionally increased, the voltage conversion module is directly shut down, and more power consumption can be saved; the service life of the switching power supply is prolonged; and potential safety hazards are reduced.

Description

Technical Field

[0001] The utility model relates to the field of power supplies, in particular to a switching power supply. Background Art

[0002] With the popularity and application of mobile devices such as mobile phones, tablets, and power tools, people's demand for high-performance battery charging management chips has also increased significantly. Most people are used to using switching power supplies. Once they are plugged into a power socket, they will not be unplugged. In this way, even when the mobile device is not connected to the switching power supply for charging, the switching power supply will still have standby power consumption.

[0003] like Figure 1 As shown in the figure, after the switching power supply is connected to the AC power supply, the power input module converts the AC mains into a DC voltage. The power management controller obtains power from the power input module through the power supply access module, and after power-on, controls the voltage conversion module to convert the DC voltage output by the power input module to generate a stable DC voltage to power the secondary load. Although some switching power supplies have a standby working mode, even if they enter the standby working mode, their output drive part still needs to be powered on, so there are the following disadvantages: 1. It consumes more power; 2. It reduces the life of the switching power supply; 3. The power management controller has to output the drive signal all the time, which also brings safety hazards. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a switching power supply in view of the above technical defects in the prior art.

[0005] The technical solution adopted by the utility model to solve the technical problem is: construct a switching power supply, including a power input module, a power supply access module, a power management controller, a voltage conversion module, an auxiliary power supply module, and also includes a switch for user operation; the power management controller includes:

[0006] a control pin connected to the switch;

[0007] A power supply unit connected to the power supply access module and the auxiliary power supply module, and used to obtain the power supply voltage from the power input module through the power supply access module in the shutdown state and obtain the power supply voltage from the auxiliary power supply module and the power supply access module in the working state, and perform voltage processing on the power supply voltage;

[0008] A detection unit connected to the control pin and the power supply unit, and used to draw power from the power supply unit, receive the operation signal of the switch through the control pin, and determine the current state, wherein the state includes a working state and a shutdown state;

[0009] A control unit connected to the detection unit and used for generating a control signal required by the voltage conversion module when the detection unit determines that the current state is a working state.

[0010] Preferably, the power supply unit comprises:

[0011] A clamping circuit for clamping the power supply voltage;

[0012] A step-down circuit for stepping down the clamped power supply voltage.

[0013] Preferably, the detection unit includes a comparator, a pull-up device, an oscillator, and a delay filter; wherein,

[0014] The power supply end of the comparator, the power supply end of the oscillator, and the power supply end of the delay filter are respectively connected to the output end of the power supply unit, the first end of the switch is grounded, the first input end of the comparator is respectively connected to the second end of the switch and the first end of the pull-up device, the second end of the pull-up device is connected to the output end of the power supply unit, the second input end of the comparator inputs a reference voltage, the output end of the comparator is connected to the input end of the delay filter, the clock end of the delay filter is connected to the output end of the oscillator, and the output end of the delay filter is connected to the input end of the control unit.

[0015] Preferably, the switch is a bounce switch, and the detection unit further comprises:

[0016] A state updating unit connected to the delay filter and used for drawing power from the power supply unit and changing according to an output signal of the delay filter.

[0017] Preferably, the state updating unit cycles between the working state and the shutdown state according to each action of the bounce switch.

[0018] Preferably, the pull-up device is a pull-up resistor or a constant current source.

[0019] Preferably, the power supply access module includes a first resistor, and a first end of the first resistor is connected to an output end of the power input module, and a second end of the first resistor is connected to a power pin of the power management controller.

[0020] Preferably, when the switching power supply is a flyback converter, the voltage conversion module includes a transformer with an auxiliary winding;

[0021] The auxiliary power supply module includes a first diode and a second resistor, wherein the first end of the auxiliary winding is connected to the anode of the first diode, and the cathode of the first diode is connected to the power pin of the power management controller through the second resistor.

[0022] Preferably, it also includes:

[0023] An indication module for indicating the state of the switching power supply.

[0024] Preferably, the indication module includes an LED indicator light, a second diode, and a capacitor, the positive electrode of the second diode is connected to the first end of the auxiliary winding, the negative electrode of the second diode is respectively connected to the positive end of the LED indicator light, the first end of the capacitor, and the positive electrode of the first diode, the negative end of the LED indicator light and the second end of the capacitor are grounded, and the second end of the auxiliary winding is grounded.

[0025] In implementing the technical solution of the utility model, since the power supply of the detection unit for the switch operation detection and state judgment is provided by the power supply unit, and in the shutdown state, the power supply unit directly draws power from the power input module through the power supply access module, so as long as the switch power supply is connected to the external power supply, the detection unit can be powered on and work without relying on the voltage conversion module and the auxiliary power supply module. Therefore, when the switch power supply does not need to supply power to the secondary load, the user can perform the corresponding shutdown operation through the switch, and the detection unit can determine that the current state is the shutdown state after detecting the operation signal, and the control unit no longer generates the control signal required by the voltage conversion module, that is, the voltage conversion process is no longer performed. When the switch power supply needs to supply power to the secondary load again, the user can perform the corresponding power-on operation through the switch, and the detection unit can determine that the current state is the working state after detecting the operation signal, and the control unit further generates the control signal required by the voltage conversion module, that is, the voltage conversion process is started. Therefore, compared with the prior art, it has the following beneficial effects:

[0026] 1. When there is no need to power the secondary load, the voltage conversion module can be directly shut down without increasing power consumption, which can save more power consumption;

[0027] 2. Extend the life of the switching power supply;

[0028] 3. The control unit in the power management controller does not need to output control signals to the voltage conversion module all the time, reducing safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0030] Figure 1 It is a circuit diagram of an existing switching power supply;

[0031] Figure 2 This is a logical structure diagram of the first embodiment of the switching power supply of the utility model;

[0032] Figure 3This is a circuit diagram of the second embodiment of the switching power supply of the utility model;

[0033] Figure 4 yes Figure 3 Internal logic diagram of the first embodiment of the power management controller;

[0034] Figure 5 This is a circuit diagram of Embodiment 3 of the power management controller of the utility model. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0036] First of all, although some switching power supplies in the prior art have a standby working mode, even if the switching power supply enters the standby working mode, its output driving part still needs to be powered on, because: when an external switch is set for the user to switch the state, the detection unit used to detect the operation of the switch needs to be powered on all the time, and the existing power supply method is to draw power from the auxiliary winding of the transformer, which requires: even in the standby mode, the driving part (switch tube, transformer) must always work, so the switching power supply has the defects of high power consumption, short life, and great safety hazards.

[0037] Figure 21 is a logical structure diagram of the first embodiment of the switching power supply of the utility model. The switching power supply of this embodiment includes a power input module 11, a power supply access module 12, a power management controller 13, a voltage conversion module 14, a switch 15, and an auxiliary power supply module 16. Among them, the switch 15 is used for user operation. The power management controller 13 includes: a power supply unit 131, a detection unit 132, a control unit 133 and a control pin 134. Moreover, in the power management controller 13, the control pin 134 is connected to the switch 15; the power supply unit 131 is connected to the power supply access module 12 and the auxiliary power supply module 16, and is used to obtain the power supply voltage from the power input module 11 through the power supply access module 12 in the shutdown state, and to obtain the power supply voltage from the auxiliary power supply module 16 and the power supply access module 12 in the working state, and perform voltage processing on the power supply voltage; the detection unit 132 is connected to the control pin 134 and the power supply unit 131, and is used to draw power from the power supply unit 131, and receive the operation signal of the switch through the control pin 134 and determine the current state, wherein the state includes the working state and the shutdown state; the control unit 133 is connected to the detection unit 132, and is used to generate the control signal required by the voltage conversion module 14 when the detection unit 132 determines that the current state is the working state.

[0038] Through the technical solution of this embodiment, since the power supply of the detection unit 132 for detecting the switch operation signal and judging the state is provided by the power supply unit 131, and the power supply unit 131 directly draws power from the power input module 11 through the power supply access module 12 in the shutdown state, as long as the switch power supply is connected to the external power supply, the detection unit 132 can be powered on and work without relying on the voltage conversion module 14 and the auxiliary power supply module 16. Therefore, when the switch power supply does not need to supply power to the secondary load, the user can perform the corresponding shutdown operation through the switch 15, and the detection unit 132 can determine that the current state is shutdown after detecting the operation signal, and the control unit 133 no longer generates the control signal required by the voltage conversion module 14, that is, no voltage conversion processing is performed. When the switch power supply needs to supply power to the secondary load again, the user can perform the corresponding power-on operation through the switch 15, and the detection unit 132 can determine that the current state is working after detecting the operation signal, and the control unit 133 further generates the control signal required by the voltage conversion module 14, that is, the voltage conversion processing is started. Therefore, compared with the prior art, it has the following beneficial effects:

[0039] 1. When there is no need to power the secondary load, the voltage conversion module can be directly shut down without increasing power consumption, which can save more power consumption;

[0040] 2. Extend the life of the switching power supply;

[0041] 3. The control unit in the power management controller does not need to output control signals to the voltage conversion module all the time, reducing safety risks.

[0042] Figure 3 This is a circuit diagram of the second embodiment of the switching power supply of the utility model. The switching power supply of this embodiment is a flyback converter and includes a power input module 11, a power access module 12, a power management controller 13, a voltage conversion module 14, a switch 15 and an auxiliary power supply module 16. Among them, the power input module 11 includes a diode rectifier bridge for converting the AC power supply voltage into a DC voltage; the power access module 12 includes a resistor (a first resistor), and the first end of the resistor is connected to the output end of the power input module 11, and the second end of the resistor is connected to the power pin (VCC) of the power management controller 13 to limit the power supply current of the power management controller 13; the switch 15 can be, for example, a pop-up switch SW; the voltage conversion module 14 includes a switch tube and a transformer with an auxiliary winding; the auxiliary power supply module 16 includes a diode 161 and a resistor 162, wherein the positive electrode of the diode 161 is connected to the first end (different-name end) of the auxiliary winding, and the negative electrode of the diode 161 is connected to the power pin (VCC) of the power management controller 13 through the resistor 162.

[0043] Recombination Figure 4 The power management controller 13 includes a power supply unit 131, a detection unit 132, a control unit 133 and a control pin CTR.

[0044] like Figure 4 As shown, the power supply unit 131 includes a clamping circuit 1311 and a buck circuit 1312. The clamping circuit 1311 is used to clamp the power voltage on the power pin (VCC) to prevent the chip protection function from being triggered when the power voltage is too large; the buck circuit 1312 is used to buck the clamped power voltage.

[0045] like Figure 4As shown, the detection unit 132 includes a pull-up device 1321, a comparator 1322, an oscillator 1323, a delay filter 1324 and a state update unit 1325, wherein the oscillator 1323 is used to generate a clock signal; the delay filter 1324 is used to delay and filter the output signal of the comparator 1322 according to the clock signal, thereby preventing the false triggering caused by the jitter of the switch SW; the state update unit 1325 is used to change according to the output signal of the delay filter 1324, specifically, according to each action of the pop-up switch SW, cyclically switch between the working state and the shutdown state. The pull-up device 1321 is a constant current source in this embodiment, and of course it can also be a pull-up resistor in other embodiments. In addition, in this embodiment, the power supply end of the comparator 1322, the power supply end of the oscillator 1323, the power supply end of the delay filter 1324, and the power supply end of the state update unit are all connected to the output end of the power supply unit 131, that is, connected to the output end of the step-down circuit 1312. The first end of the switch SW is grounded, the second end of the switch SW is connected to the first input end of the comparator 1322, the first input end of the comparator 1322 is also connected to the output end of the power supply unit 131 through the pull-up device 1321, the second input end of the comparator 1322 inputs the reference voltage (V0), the output end of the comparator 1322 is connected to the input end of the delay filter 1324, the clock end of the delay filter 1324 is connected to the output end of the oscillator 1323, the output end of the delay filter 1324 is connected to the input end of the state update unit 1325, and the output end of the state update unit 1325 outputs a state signal.

[0046] Combine the following Figure 3 and Figure 4 The working principle of the switching power supply of this embodiment is described as follows:

[0047] When the switch power supply is connected to the external power supply, the power input module 11 converts the voltage of the external power supply into a DC voltage, and connects it to the power pin (VCC) of the power management controller 13 through the power supply access module (first resistor) 12. Moreover, when the power supply voltage of the power management controller 13 reaches the start voltage (VCC_ON), ​​VCC enable is issued. At the same time, after the power supply voltage is clamped and reduced by the power supply unit 131, the control pin CTR is not only pulled up by the constant current source 1321, but also the detection unit 132 is powered to start working. Since the power supply voltage is provided by the power input module 11 through the power supply access module 12, the power supply unit 131, the detection unit 132, the oscillator 1323, the delay filter 1324, and the state update unit 1325 do not need to rely on the voltage conversion module 14 and the auxiliary power supply module 16 to work. Moreover, the power management controller 13 will not issue a drive before detecting the operation signal of the switch SW, so the power consumption is also very low.

[0048] When the current state is the shutdown state, if the user wants to power the secondary load, the bounce switch SW can be operated. At this time, the control pin CTR will generate a short low level. In this way, during this period, since the voltage at the first input terminal of the comparator 1322 is lower than the reference voltage V0, an output signal is generated and sent to the delay filter 1324 for delay filtering. If the delay time is met, a signal is output to the state update unit 1325, so that the state update unit 1325 switches the current state from the shutdown state to the working state according to the action of the bounce switch SW. Finally, the control unit 133 generates the required control signal to the voltage conversion module 14 when the current state is the working state, so that the voltage conversion module 14 performs voltage conversion processing and supplies power to the secondary load. It should be noted here that when the signal on the control pin CTR is pulled down, the signal must meet a certain time, such as 100ms, so as to avoid false triggering caused by jitter, so the oscillator 1323 and the delay filter 1324 are introduced.

[0049] When the current state is the working state, if the user does not need to power the secondary load, the bounce switch SW can be operated again. At this time, the control pin CTR will generate a short low level. In this way, during this period, since the voltage at the first input terminal of the comparator 1322 is lower than the reference voltage V0, an output signal is generated and sent to the delay filter 1324 for delay filtering. If the delay time is met, a signal is output to the state update unit 1325, so that the state update unit 1325 switches the current state from the working state to the shutdown state according to the action of the bounce switch SW. Finally, the control unit 133 stops generating the required control signal to the voltage conversion module 14 when the current state is the shutdown state, so that the voltage conversion module stops performing voltage conversion processing.

[0050] It should also be noted that when the switch SW is a bounce switch, the triggering of the switch SW to pull down the control pin CTR can be repeated, for example, on→off→on→off…. It should also be noted that due to different types of switches SW, the operation signal provided can be a pulse signal or a long-term high / low level signal. When it is a long-term high / low level signal, the state updating unit 1325 in the above embodiment can be omitted. In this way, if the switch SW is in the open state, the voltage at the first input terminal of the comparator 1322 is higher than the reference voltage V0, and when the switch SW is in the closed state, the voltage at the first input terminal of the comparator 1322 is lower than the reference voltage V0. Therefore, the signal output by the comparator 1322 is different when the state of the switch SW is different. After the output signal is delayed and filtered by the delay filter 1324, it can be directly determined whether the current state is the working state or the shutdown state.

[0051] Figure 5 This is a circuit diagram of the third embodiment of the switching power supply of the utility model. Figure 3 The embodiment shown is different in that it also includes an indication module 17, which is used to indicate the working state of the switching power supply.

[0052] Furthermore, if Figure 5 As shown, the indication module 17 includes a diode 171 (a second diode), a current limiting resistor 172, an LED indicator light 173 and a capacitor 174, wherein the positive end of the diode 171 is connected to the first end (the opposite end) of the auxiliary winding, and the negative end of the diode 171 is connected to the positive end of the diode 161. The positive end of the LED indicator light 173 is connected to the negative end of the diode 171 through the current limiting resistor 172, the negative end of the LED indicator light 173 is grounded, the second end (the same end) of the auxiliary winding is grounded, and the capacitor 174 is connected between the negative end of the diode 171 and the ground.

[0053] Regarding the above embodiment, it should be noted that, because when using an external switch SW to control the state of the switching power supply, it is difficult for the user to know the current state and whether the current output has power, so an indication module is introduced. Figure 5 As shown, the indicator module includes an LED indicator 173, and when the power management controller 13 has a driving signal, the transformer works, its auxiliary winding is powered on, and the LED indicator 173 will light up; if the power management controller 13 has no driving signal for a long time, the transformer stops working, its auxiliary winding loses power, and the LED indicator 173 will go out. If the switching power supply needs to work again, the user needs to re-operate the switch SW.

[0054] The above description is only the preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the scope of the claims of the utility model.

Claims

1. A switching power supply, comprising a power input module, a power supply access module, a power management controller, a voltage conversion module, and an auxiliary power supply module, characterized in that: Also includes a switch for user operation; the power management controller includes: a control pin connected to the switch; A power supply unit connected to the power supply access module and the auxiliary power supply module, and used to obtain the power supply voltage from the power input module through the power supply access module in the shutdown state and obtain the power supply voltage from the auxiliary power supply module and the power supply access module in the working state, and perform voltage processing on the power supply voltage; A detection unit connected to the control pin and the power supply unit, and used to draw power from the power supply unit, receive the operation signal of the switch through the control pin, and determine the current state, wherein the state includes a working state and a shutdown state; A control unit connected to the detection unit and used for generating a control signal required by the voltage conversion module when the detection unit determines that the current state is a working state.

2. The switching power supply according to claim 1, characterized in that: The power supply unit comprises: A clamping circuit for clamping the power supply voltage; A step-down circuit for stepping down the clamped power supply voltage.

3. The switching power supply according to claim 1, characterized in that: The detection unit includes a comparator, a pull-up device, an oscillator, and a delay filter; wherein, The power supply end of the comparator, the power supply end of the oscillator, and the power supply end of the delay filter are respectively connected to the output end of the power supply unit, the first end of the switch is grounded, the first input end of the comparator is respectively connected to the second end of the switch and the first end of the pull-up device, the second end of the pull-up device is connected to the output end of the power supply unit, the second input end of the comparator inputs a reference voltage, the output end of the comparator is connected to the input end of the delay filter, the clock end of the delay filter is connected to the output end of the oscillator, and the output end of the delay filter is connected to the input end of the control unit.

4. The switching power supply according to claim 3, characterized in that: The switch is a bounce switch, and the detection unit further comprises: A state updating unit connected to the delay filter and used for drawing power from the power supply unit and changing according to an output signal of the delay filter.

5. The switching power supply according to claim 4, characterized in that: The state updating unit cycles between the working state and the shutdown state according to each action of the bounce switch.

6. The switching power supply according to claim 3, characterized in that: The pull-up device is a pull-up resistor or a constant current source.

7. The switching power supply according to claim 1, characterized in that: The power supply access module includes a first resistor, and a first end of the first resistor is connected to an output end of the power input module, and a second end of the first resistor is connected to a power pin of the power management controller.

8. The switching power supply according to claim 1, characterized in that: When the switching power supply is a flyback converter, the voltage conversion module includes a transformer with an auxiliary winding; The auxiliary power supply module includes a first diode and a second resistor, wherein the first end of the auxiliary winding is connected to the anode of the first diode, and the cathode of the first diode is connected to the power pin of the power management controller through the second resistor.

9. The switching power supply according to claim 8, characterized in that: Also includes: An indication module for indicating the state of the switching power supply.

10. The switching power supply according to claim 9, characterized in that: The indication module includes an LED indicator light, a second diode, and a capacitor, wherein the anode of the second diode is connected to the first end of the auxiliary winding, the cathode of the second diode is respectively connected to the positive end of the LED indicator light, the first end of the capacitor, and the anode of the first diode, the negative end of the LED indicator light and the second end of the capacitor are grounded, and the second end of the auxiliary winding is grounded.

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