Multipath output time sequence control circuit based on switching power supply

Abstract

The utility model discloses a multipath output time sequence control circuit based on a switching power supply. The multipath output time sequence control circuit comprises an optocoupler control circuit, an optocoupler circuit, a main path feedback time-delay circuit, an auxiliary path time-delay control circuit and an auxiliary path switching circuit which are connected in sequence. The optocoupler control circuit is connected with an input bus power supply, and the voltage of the optocoupler circuit, the voltage of the auxiliary circuit delay control circuit and the voltage of the main circuit feedback delay circuit all adopt the output voltage of the switching power supply. According to the utility model, an analog circuit is adopted, and time sequence control with different requirements can be realized only by changing component parameters, so that the development cycle of a product can be greatly shortened, and the cost of a power supply can be reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of switching power supplies, and specifically relates to a multi-channel output timing control circuit based on a switching power supply. Background Art

[0002] Since the system power supply of traditional industry and power industry needs to provide stable multi-channel output voltage for various loads, and the switching power supply needs certain on / off timing requirements for various output voltages to ensure the normal operation of the switching power supply, most of the existing switching power supplies on the market use digital DSP chips to collect the input voltage and output voltage of different loads as a reference, and use optocouplers to control the on / off timing of multiple output voltages in the system power supply. This kind of on / off timing circuit that controls multiple output voltages through DSP chips requires a lot of manpower and material resources, and requires software and hardware engineers to cooperate with each other to complete such work, which greatly increases the product development cycle and cost. The existing switching power supplies in traditional industry and power industry on the market often have very strict cost control of products. Utility Model Content

[0003] Aiming at the above problems existing in the multi-channel output timing control of the switching power supply, the utility model proposes a multi-channel output timing control circuit based on the switching power supply, which can greatly shorten the product development cycle and reduce the cost of the power supply.

[0004] The technical solution of the utility model to solve the above technical problems is as follows:

[0005] A multi-channel output timing control circuit based on a switching power supply comprises an optocoupler control circuit, an optocoupler circuit, a main channel feedback delay circuit, an auxiliary channel delay control circuit and an auxiliary channel switch circuit which are connected in sequence; the optocoupler control circuit is connected to an input bus power supply, and the voltages of the optocoupler circuit, the auxiliary channel delay control circuit and the main channel feedback delay circuit all adopt the output voltage of the switching power supply.

[0006] Furthermore, the optocoupler control circuit includes a bus voltage, a voltage-stabilizing diode D13, a current-limiting resistor, a filter circuit and an optocoupler OC3 connected in sequence, the cathode of the voltage-stabilizing diode D13 is connected to the bus voltage, the anode is connected to the current-limiting resistor, and the filter circuit is connected to the output end.

[0007] The beneficial effect of the above further solution is that a switching signal is provided for the optocoupler circuit, and the sizes of various voltage-stabilizing diodes and current-limiting resistors can be flexibly matched to ensure that the optocoupler is turned on or off within a set range.

[0008] Furthermore, the current limiting resistor is a cascaded parallel resistor, specifically including a first parallel resistor R76 and R87, a second parallel resistor R77 and R88, a third parallel resistor R79 and R89, and a fourth parallel resistor R78 and R90; the filtering circuit includes parallel capacitors C57 and C62.

[0009] Furthermore, the optocoupler circuit includes an optocoupler OC3, a current limiting resistor R91 and a voltage zener diode D16 connected in series, the output end of the filter circuit is respectively connected to the positive and negative electrodes of the optocoupler OC3, the emitter of the optocoupler OC3 is connected to the cathode of the voltage zener diode D16, and the collector of the optocoupler OC3 is connected to +24V.

[0010] The beneficial effect of the above further solution is: controlling the optical coupler to provide a feedback signal and a switching function.

[0011] Furthermore, the main feedback delay circuit includes a +5V voltage, series-connected current limiting resistors R74 and R75, a voltage regulator diode D17, diodes D14 and D15, an electrolytic capacitor C53 and an optocoupler U4; the two ends of the current limiting resistor R74 are connected to the positive and negative electrodes of the optocoupler U4, the collector of the optocoupler U4 is connected to the current limiting resistor R91 of the optocoupler circuit, and the emitter of the optocoupler U4 is connected to the auxiliary delay control circuit.

[0012] The beneficial effect of the above further scheme is: the +5V main voltage forms a delay circuit through the current limiting resistors R74, R75, the voltage zener diode D17, the diodes D14, D15, the electrolytic capacitor C53 and the optical coupler U4, and the capacitor C53 is charged through the D14 diode. After a certain period of time, the voltage across the capacitor is stable, and the voltage zener diode D17 works normally, and the optical coupler U4 is turned on. When the power is turned off, when there is no output voltage of +5V, the capacitor C53 is discharged through the D15 diode to maintain the stability of the +5V output voltage. The shutdown timing is controlled by this circuit. When the input bus voltage is lower than the reverse voltage of the voltage zener diode D17 or the current is less than the working current of the optical coupler OC3, the optical coupler OC3 does not work, and the +5V output main voltage is slower than the +24V voltage. The specific shutdown time is controlled by adjusting the size of the C53 capacitor, the current limiting resistor R75, and the voltage zener diode D17, which is more convenient.

[0013] Furthermore, the auxiliary delay control circuit includes parallel capacitors C59, C58 and C63, and a voltage-stabilized power supply U6, the cathode and anode of the voltage-stabilized power supply U6 are respectively connected to the two ends of the parallel capacitor, and the capacitor C58 is an electrolytic capacitor; the positive electrode of the capacitor C58 is connected to the cathode of the voltage-stabilized power supply U6; the cathode of the voltage-stabilized power supply U6 is connected to the reference end, and the anode of the voltage-stabilized power supply U6 is connected to +24V.

[0014] The beneficial effect of the above further scheme is that the current limiting resistor R91 charges the capacitors C58, C59, and C63 to keep the voltage-stabilized power supply U6 stable, ensuring that the +24V controls the MOS tube Q3 to conduct through the feedback circuit formed by the optocoupler OC3. The +24V output auxiliary voltage starts up a certain time later than the 5V output main voltage. The specific startup time is achieved by adjusting the resistor R91 and the capacitors C58, C59, and C63.

[0015] Furthermore, the auxiliary switch circuit includes a MOS tube Q3, a resistor R35 is connected between the gate and source of the MOS tube Q3, and the source and drain of the MOS tube Q3 are both connected to 24V-.

[0016] Furthermore, it also includes an auxiliary +24V power supply circuit, which includes a transformer T2-D, a diode D10 and an inductor L4 connected in sequence.

[0017] Furthermore, it also includes an absorption circuit, which is connected in parallel with the diode D10, and the absorption circuit includes a capacitor C65 and parallel resistors R43 and R71.

[0018] The beneficial effects of the above further solution are: absorbing the stress spike of the diode D10, ensuring that the voltage stress of the diode D10 meets the diode requirements, and also effectively controlling the high-frequency noise and optimizing the output ripple.

[0019] Furthermore, it also includes a protection circuit and a filter capacitor connected in parallel at the output end, the protection circuit is a transient suppression diode D12, the filter capacitors are capacitors C48, C52, C50, C49, C64, and the filter capacitors are connected in parallel at the +24V output end.

[0020] The beneficial effects of the above further scheme are: the transient suppression diode D12 controls the +24V voltage at the moment of power-on to play a protective role, and the filter capacitor filters out the noise of the DC power supply to make the output smoother.

[0021] This application adopts the above technical solution, which has at least the following beneficial effects:

[0022] The utility model adopts an analog circuit. When the power is turned on, the main circuit outputs first, and the auxiliary circuit delays the output, and the delay time is determined by the component parameters of the auxiliary circuit delay control circuit. When the power is turned off, the auxiliary circuit is closed first, and the main circuit is delayed to close, and the delay time is determined by the component parameters of the main circuit feedback delay circuit. Therefore, if the multi-channel output of the switching circuit requires different timing control, it is only necessary to change the corresponding component parameters, which can greatly reduce the product development cycle and reduce the cost of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a principle block diagram of the utility model;

[0024] Figure 2 This is the optocoupler control circuit diagram of the utility model;

[0025] Figure 3 This is the main feedback delay circuit diagram of the utility model;

[0026] Figure 4 It is the auxiliary circuit delay control circuit, auxiliary circuit switch circuit and 24V circuit principle diagram of the utility model;

[0027] Figure 5 It is the overall circuit diagram of the utility model. DETAILED DESCRIPTION

[0028] Now, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the accompanying drawings are merely exemplary, intended to explain the principles and spirit of the present invention, rather than to limit the scope of the present invention.

[0029] like Figure 1 As shown, the utility model provides a multi-channel output timing control circuit based on a switching power supply, including an optocoupler control circuit, an optocoupler circuit, a main feedback delay circuit, an auxiliary delay control circuit and an auxiliary switch circuit connected in sequence; the optocoupler control circuit is connected to the input bus power supply, and the voltages of the optocoupler circuit, the auxiliary delay control circuit and the main feedback delay circuit all use the output voltage of the switching power supply. In this embodiment, two common voltages of the switching power supply +5V and +24V are listed, and other voltages are also applicable, which will not be described in this article.

[0030] Specifically, when the power supply is turned on normally, the main voltage is output normally, the optocoupler control circuit converts the collected input bus voltage signal and outputs a control signal to the optocoupler circuit; the optocoupler circuit is turned on according to the received control signal and sent to the main feedback delay circuit; the main feedback delay circuit receives the main voltage signal and the turn-on signal of the optocoupler circuit, the main feedback circuit starts to charge, and when charged to a certain value, it sends a high-level signal to the auxiliary delay control circuit; when the auxiliary delay control circuit receives the high-level signal from the main feedback delay circuit, it sends a turn-on signal to the auxiliary switch circuit; the auxiliary switch circuit turns on the auxiliary voltage according to the received turn-on signal, so that the auxiliary voltage is output normally, and therefore, the main voltage is output before the auxiliary voltage. When the power supply is shut down normally, the main feedback delay circuit receives the disconnection signal from the optocoupler circuit, and the main feedback circuit starts to discharge, causing the main circuit to be powered off with a delay, and sends a low-level signal to the auxiliary delay control circuit; when the auxiliary delay control circuit receives the low-level signal from the main feedback delay circuit, it sends a disconnection signal to the auxiliary switch circuit; the auxiliary switch circuit disconnects the auxiliary voltage according to the received disconnection signal, and due to the main circuit delayed discharge, the auxiliary voltage stops outputting before the main voltage.

[0031] like Figure 2 As shown, the optocoupler control circuit includes a bus voltage, a voltage-stabilizing diode D13, a current-limiting resistor, a filter circuit and an optocoupler OC3 connected in sequence, wherein the cathode of the voltage-stabilizing diode D13 is connected to the bus voltage, the anode is connected to the current-limiting resistor, and the filter circuit is connected to the output end.

[0032] Specifically, the current limiting resistor is a cascaded parallel resistor, specifically including a first parallel resistor R76 and R87, a second parallel resistor R77 and R88, a third parallel resistor R79 and R89, and a fourth parallel resistor R78 and R90; the filtering circuit includes parallel capacitors C57 and C62.

[0033] The advantage of this part of the optocoupler control circuit is that it can flexibly match the size of various voltage-regulating diodes and current-limiting resistors to ensure that the optocoupler is turned on or off within the set range.

[0034] like Figure 3 As shown, the optocoupler circuit includes an optocoupler OC3, a current limiting resistor R91 and a voltage zener diode D16 connected in series, the output end of the filter circuit in the optocoupler control circuit is respectively connected to the positive and negative electrodes of the optocoupler OC3, the emitter of the optocoupler OC3 is connected to the cathode of the voltage zener diode D16, and the collector of the optocoupler OC3 is connected to +24V.

[0035] The main feedback delay circuit includes a +5V voltage, series-connected current limiting resistors R74 and R75, a voltage stabilizing diode D17, diodes D14 and D15, an electrolytic capacitor C53 and an optocoupler U4; the two ends of the current limiting resistor R74 are connected to the positive and negative electrodes of the optocoupler U4, the collector of the optocoupler U4 is connected to the current limiting resistor R91 of the optocoupler circuit, and the emitter of the optocoupler U4 is connected to the auxiliary delay control circuit.

[0036] The working process of the optocoupler circuit and the main feedback delay circuit is as follows: when the power is turned on, the current through the optocoupler OC3 is greater than the working current of the optocoupler, and the optocoupler OC3 works normally. The +5V main voltage passes through the current limiting resistors R74, R75, the voltage zener diode D17, the diodes D14, D15, the electrolytic capacitor C53 and the optocoupler U4 to form a delay circuit, and the capacitor C53 is charged through the diode D14. After a certain period of time, the voltage across the capacitor C53 is stable, and the voltage zener diode D17 works normally, and the optocoupler U4 is turned on. When the power is turned off, the electrolytic capacitor C53 discharges through the diode D15, which delays the closing of the +5V main voltage.

[0037] This part of the +5V delay circuit is simple and can be used with various multi-channel circuits without affecting product performance.

[0038] like Figure 4As shown, the auxiliary delay control circuit includes parallel capacitors C59, C58 and C63, and a voltage-stabilized power supply U6, the cathode and anode of the voltage-stabilized power supply U6 are respectively connected to the two ends of the parallel capacitor, and the capacitor C58 is an electrolytic capacitor; the positive electrode of the capacitor C58 is connected to the cathode of the voltage-stabilized power supply U6; the cathode of the voltage-stabilized power supply U6 is connected to the reference end, and the anode of the voltage-stabilized power supply U6 is connected to +24V. The auxiliary switch circuit includes a MOS tube Q3, a resistor R35 is connected between the gate and source of the MOS tube Q3, and the source and drain of the MOS tube Q3 are both connected to 24V-.

[0039] The entire working process of the auxiliary delay control circuit and the auxiliary switch circuit is as follows: capacitors C59, C58, C63, resistor R35, MOS tube Q3 and voltage regulator U6 form a switch circuit to control the on and off of MOS tube Q3. Capacitors C59, C58, C63 charge through the current limiting resistor R91 to keep the voltage regulator U6 stable, thereby controlling the on and off of Q3 to control the on / off timing of the +24V output voltage. Capacitors C59, C58, C63 charge through the current limiting resistor R91 to keep the voltage regulator U6 stable to control the on and off of MOS tube Q3, thereby controlling the on / off timing of the +24V output voltage. The voltage regulator U6 can use a controllable precision voltage regulator TL431.

[0040] This embodiment also provides an auxiliary +24V power supply circuit, such as Figure 4 As shown, the auxiliary +24V power supply circuit includes a transformer T2-D, a diode D10 and an inductor L4 connected in sequence. After the transformer T2-D steps down the 220V voltage, it is rectified by the diode D10 to become a pulsating direct current, and the direct current passes through the inductor L4 and the filter capacitors C48, C52, C50, C49, and C64 to output a stable +24V. For the +5V power supply circuit, the existing power supply circuit can be used, so it will not be described in detail in this article.

[0041] The auxiliary +24V power supply circuit also includes an absorption circuit, which is connected in parallel with the diode D10. The absorption circuit includes a capacitor C65 and parallel resistors R43 and R71. The absorption circuit absorbs the stress spike of the diode D10 to ensure that the voltage stress of the D10 diode meets the diode requirements, and also effectively controls high-frequency noise to optimize the output ripple. The resistor R14 is a +24V output dummy load to ensure that the +24V voltage is stable when unloaded.

[0042] In addition, in order to protect the auxiliary +24V power supply circuit, a protection circuit can be connected in parallel at the output end. The protection circuit is a transient suppression diode D12, and the transient suppression diode D12 controls the +24V voltage at the moment of startup.

[0043] Figure 5The general circuit diagram of the utility model is as follows: when the power supply is turned on normally, the +5V output main voltage works normally, the input bus voltage is higher than the reverse breakdown voltage of the voltage stabilizing diode D13, and the current size on the current limiting resistors R76, R77, R78, R79, R87, R88, R89, and R90 is used to control the on and off of the optocoupler OC3. When the current is greater than the working current of the optocoupler OC3, the optocoupler OC3 is turned on, and the current limiting resistor R91 charges the capacitors C58, C59, and C63 to keep the voltage stabilizing power supply U6 stable, ensuring that the +24V controls the MOS tube Q3 to turn on through the feedback circuit formed by the optocoupler OC3. The +24V output auxiliary voltage starts up a certain time later than the 5V output main voltage. The specific startup time is achieved by adjusting the resistor R91 and the capacitors C58, C59, and C63. When the power is turned off and there is no +5V output voltage, the electrolytic capacitor C53 discharges through the diode D15 to maintain the stability of the +5V output voltage. This circuit is used to control the shutdown timing. When the input bus voltage is lower than the reverse voltage of the voltage-stabilizing diode D17 or the current is less than the operating current of the optocoupler OC3, the optocoupler OC3 does not work, and the +5V output main voltage shuts down slower than the +24V voltage. The specific shutdown time is controlled by adjusting the size of the C53 capacitor, the current-limiting resistor R75, and the voltage-stabilizing diode D17.

[0044] The key point of the utility model is to utilize the phenomenon that the voltage zener diode is in a reverse breakdown state when working normally, and its current can change within a wide range while the voltage remains basically unchanged, accurately collect the input bus voltage through the resistor voltage division and current limiting effect, control the optocoupler to provide feedback signal and switch effect, and accurately control the switch timing of multiple output voltages through a circuit composed of resistors, capacitors, TL431 reference, diodes, MOS tubes and other devices.

[0045] This embodiment only proposes two situations of the main +5V and auxiliary +24V output of the switching power supply, and the power on / off timing is: when normally turned on, the +5V power supply is turned on first, and the +24V power supply is turned on after a delay; when turned off, the +24V power supply is turned off first, and the +5V power supply is turned off after a delay due to discharge. As for the delay time, its parameters can be determined by the corresponding delay circuit and flexibly set.

[0046] Compared with the existing on-off timing circuits on the market that use DSP chips to control multiple output voltages, the utility model uses analog circuits and can achieve timing control with different requirements by simply changing its component parameters. Therefore, it can greatly shorten the product development cycle and reduce the cost of power supply.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-channel output timing control circuit based on a switching power supply, characterized in that: It includes an optocoupler control circuit, an optocoupler circuit, a main feedback delay circuit, an auxiliary delay control circuit and an auxiliary switch circuit which are connected in sequence; the optocoupler control circuit is connected to an input bus power supply, and the voltages of the optocoupler circuit, the auxiliary delay control circuit and the main feedback delay circuit all use the output voltage of the switching power supply.

2. The multi-channel output timing control circuit according to claim 1, characterized in that: The optocoupler control circuit includes a bus voltage, a voltage-stabilizing diode D13, a current-limiting resistor, a filter circuit and an optocoupler OC3 connected in sequence, wherein the cathode of the voltage-stabilizing diode D13 is connected to the bus voltage, the anode is connected to the current-limiting resistor, and the filter circuit is connected to the output end.

3. The multi-channel output timing control circuit according to claim 2, characterized in that: The current limiting resistors are cascaded parallel resistors, specifically including first parallel resistors R76 and R87, second parallel resistors R77 and R88, third parallel resistors R79 and R89, and fourth parallel resistors R78 and R90; the filtering circuit includes parallel capacitors C57 and C62.

4. The multi-channel output timing control circuit according to claim 2, characterized in that: The optocoupler circuit includes an optocoupler OC3, a current limiting resistor R91 and a voltage zener diode D16 connected in series. The output end of the filter circuit is respectively connected to the positive and negative electrodes of the optocoupler OC3, the emitter of the optocoupler OC3 is connected to the cathode of the voltage zener diode D16, and the collector of the optocoupler OC3 is connected to +24V.

5. The multi-channel output timing control circuit according to claim 4, characterized in that: The main feedback delay circuit includes a +5V voltage, current limiting resistors R74 and R75 connected in series, a voltage stabilizing diode D17, diodes D14 and D15, an electrolytic capacitor C53 and an optocoupler U4; the two ends of the current limiting resistor R74 are connected to the positive and negative electrodes of the optocoupler U4, the collector of the optocoupler U4 is connected to the current limiting resistor R91 of the optocoupler circuit, and the emitter of the optocoupler U4 is connected to the auxiliary delay control circuit.

6. The multi-channel output timing control circuit according to claim 5, characterized in that: The auxiliary delay control circuit includes parallel capacitors C59, C58 and C63, and a voltage-stabilized power supply U6, wherein the cathode and anode of the voltage-stabilized power supply U6 are respectively connected to the two ends of the parallel capacitor, and the capacitor C58 is an electrolytic capacitor; the positive electrode of the capacitor C58 is connected to the cathode of the voltage-stabilized power supply U6; the cathode of the voltage-stabilized power supply U6 is connected to the reference end, and the anode of the voltage-stabilized power supply U6 is connected to +24V.

7. The multi-channel output timing control circuit according to claim 6, characterized in that: The auxiliary switch circuit includes a MOS tube Q3, a resistor R35 is connected between the gate and source of the MOS tube Q3, and the source and drain of the MOS tube Q3 are both connected to 24V-.

8. The multi-channel output timing control circuit according to claim 1, characterized in that: It also includes an auxiliary +24V power supply circuit, which includes a transformer T2-D, a diode D10 and an inductor L4 connected in sequence.

9. The multi-channel output timing control circuit according to claim 8, characterized in that: It also includes an absorption circuit, which is connected in parallel with the diode D10. The absorption circuit includes a capacitor C65 and parallel resistors R43 and R71.

10. The multi-channel output timing control circuit according to claim 8, characterized in that: It also includes a protection circuit and a filter capacitor connected in parallel at the output end. The protection circuit is a transient suppression diode D12, and the filter capacitors are capacitors C48, C52, C50, C49, and C64. The filter capacitors are connected in parallel at the +24V output end.

Images