A constant on-time dual-channel DC power supply

Abstract

The present invention provides a dual-channel DC power supply with a constant on-time, which can output two power supplies while maintaining a constant on-time, and has a simple structure and controllable cost. It includes a DC chip, an input filter circuit, an input protection circuit, an input port, an on-time circuit, a ripple feedback circuit, a voltage feedback circuit, an output mutual inductance circuit, an output filter circuit, a first output port, and a second output port. The DC chip includes an input terminal, an on-time control interface, a voltage feedback circuit output and feedback interface, a ripple feedback circuit output and feedback interface, and an output interface. The three interfaces of the input terminal of the DC chip are independently connected to the output terminal of the input filter circuit, the output terminal of the input protection circuit, and the input port. The on-time control interface of the DC chip is connected to the on-time control circuit, and the voltage feedback circuit output interface of the DC chip is connected to the input terminal of the voltage feedback circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply structure, in particular to a dual-channel DC power supply with a constant on-time. Background Art

[0002] Existing constant on-time power supplies generally have only one power output, which makes it difficult to cope with complex circuit designs with multiple power supplies. In addition, existing multi-channel power supplies have complex structures and are more expensive than constant on-time power supplies. Therefore, in order to cope with complex circuit designs, controllable costs and simplified power supply structures are factors that must be considered. Summary of the invention

[0003] In view of the above problems, the present invention provides a dual-channel DC power supply with a constant on-time, which can output two channels of power while maintaining a constant on-time, and has a simple structure and controllable costs.

[0004] A dual-channel DC power supply with a constant on-time, characterized in that it includes a DC chip, an input filter circuit, an input protection circuit, an input port, an on-time circuit, a ripple feedback circuit, a voltage feedback circuit, an output mutual inductance circuit, an output filter circuit, a first output port, and a second output port. The DC chip includes an input end, an on-time control interface, a voltage feedback circuit output and feedback interface, a ripple feedback circuit output and feedback interface, and an output interface. The three interfaces of the input end of the DC chip are independently connected to the output end of the input filter circuit, the output end of the input protection circuit, and the input port. The on-time control interface of the DC chip is connected to the on-time control interface of ... The on-time control circuit is configured to: a voltage feedback circuit output interface of the DC chip is connected to the input end of the voltage feedback circuit, a feedback end of the voltage feedback circuit is connected to the voltage feedback circuit feedback interface of the DC chip, a ripple feedback circuit output interface of the DC chip is connected to the input end of the ripple feedback circuit, a feedback end of the ripple feedback circuit is connected to the ripple feedback circuit feedback interface of the DC chip, one of the output interfaces of the DC chip is directly connected to the first output port, another of the output interfaces of the DC chip is connected to the output mutual inductance circuit and then to the second output port, and the second output port is also externally connected to the output filter circuit.

[0005] It is further characterized by:

[0006] One end of the input filter circuit is connected to the input port and the other end is grounded, so as to filter out the ripple of the input voltage;

[0007] The input protection circuit specifically includes a resistor R1 and a resistor R5, the two resistors are connected by a connecting line, the midpoint of the connecting line of the two resistors is connected to the corresponding interface of the input end of the DC chip, one end of the input protection circuit is connected to the input port, and the other end is grounded, and the input protection circuit is used to adjust the power supply on and off according to the input voltage;

[0008] The on-time control circuit specifically includes a resistor R2, one end of the on-time control circuit is connected to the input port, and the other end is connected to the on-time control interface of the DC chip, and the on-time control circuit is used to adjust the on-time;

[0009] The ripple feedback circuit specifically includes a resistor R3, a capacitor C2, and a capacitor C6, which are used to adjust the output port ripple and control the output voltage;

[0010] The voltage feedback circuit specifically includes a resistor R4 and a resistor R6, and voltage feedback is performed through the midpoint of the two resistors to adjust the output voltage;

[0011] The output mutual inductance circuit is specifically a mutual inductance transformer, the input end of the mutual inductance transformer is connected to the first output port, and the output end of the mutual inductance transformer is connected to the second output port;

[0012] The output filter circuit specifically includes a capacitor C3 and a capacitor C4 connected in parallel, and the output filter circuit is used to filter out ripples at the output port.

[0013] After adopting the present invention, the input port part of the DC chip is provided with an input filtering circuit and an input protection circuit, which ensure the safety and stability of the input part, and then the conduction time control circuit is used to control the conduction time, and then the ripple feedback circuit and the voltage feedback circuit are used to ensure the stability and safety of the output voltage, and then the output voltage is output through the first output port, and the voltage of the second output port is output after voltage regulation through the output mutual inductance circuit, and the ripple of the second output port is filtered out through the output filtering circuit, which makes it possible to output two power supplies while keeping the conduction time constant, and the structure is simple and the cost is controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention;

[0015] Figure 2 A schematic structural connection diagram of a specific embodiment of the present invention;

[0016] The names corresponding to the serial numbers in the figure are as follows:

[0017] Input protection circuit 101, input filter circuit 102, DC chip 103, on-time control circuit 104, voltage feedback circuit 105, ripple feedback circuit 106, output mutual inductance circuit 107, output filter circuit 108, input port 109, first output port 110, second output port 111. DETAILED DESCRIPTION

[0018] A constant on-time dual-circuit DC power supply, see Figure 1 :It includes a DC chip 103, an input filter circuit 102, an input protection circuit 101, an input port 109, a conduction time circuit 104, a ripple feedback circuit 106, a voltage feedback circuit 105, an output mutual inductance circuit 107, an output filter circuit 108, a first output port 110, and a second output port 111. The DC chip 103 includes an input terminal, a conduction time control interface, a voltage feedback circuit output and feedback interface, a ripple feedback circuit output and feedback interface, and an output interface. The three interfaces of the input terminal of the DC chip 103 are independently connected to the output terminal of the input filter circuit 102, the output terminal of the input protection circuit 101, and the input port. The conduction time control interface of the DC chip 103 is connected to the conduction time The control circuit 104 is connected between the DC chip 103 and the control circuit 104, the voltage feedback circuit output interface of the DC chip 103 is connected to the input end of the voltage feedback circuit 105, the feedback end of the voltage feedback circuit 105 is connected to the voltage feedback circuit feedback interface of the DC chip 103, the ripple feedback circuit output interface of the DC chip 103 is connected to the input end of the ripple feedback circuit 106, the feedback end of the ripple feedback circuit 106 is connected to the ripple feedback circuit feedback interface of the DC chip, one of the output interfaces of the DC chip 103 is directly connected to the first output port 110, the other output interface of the DC chip 103 is connected to the output mutual inductance circuit 107 and then to the second output port 111, and the second output port 111 is also externally connected to the output filter circuit 108.

[0019] like Figure 2 , is a structural diagram of a dual-channel DC power supply with a constant on-time in this patent, which includes: an input filter circuit 102, an input protection circuit 101, an on-time control circuit 104, a DC chip 103, a ripple feedback circuit 106, a voltage feedback circuit 105, an output mutual inductance circuit 107, and an output filter circuit 108. In the embodiment of the present application, the DC chip 103 adopts a DC chip with a wide input voltage and a high frequency, which improves the compatibility of the power supply of the later circuit system; the input protection circuit 101 is adopted to prevent input overvoltage; the on-time control circuit 104 is adopted to facilitate the modification and debugging of the system on-time in the later stage, and improve the debuggability and maintainability of the dual DC power supply design. It is suitable for general complex electronic systems. One end of the input filter circuit is connected to the input port and the other end is grounded, which is used to filter out the ripple of the input voltage.

[0020] The DC power chip uses a wide input voltage, high frequency TI power chip, model LM5017, for dual output; for the selection of power switching frequency, reference is made to the system design requirements, and the relationship in the chip data sheet is used for calculation.

[0021] The input filter circuit is specifically a capacitor C5, one end of which is connected to the input port and the other end is grounded, and is used to filter out the ripple of the input voltage;

[0022] The input protection circuit specifically includes resistor R1 and resistor R5. The two resistors are connected by a connecting line. The midpoint of the connecting line between the two resistors is connected to the corresponding interface of the input end of the DC chip. One end of the input protection circuit is connected to the input port and the other end is grounded. The input protection circuit is used to adjust the power supply on and off according to the input voltage; the input protection circuit is implemented in the form of a voltage divider connected in series with resistors R1 and R5 to prevent the input voltage from being too high or too low to damage the chip.

[0023] The on-time control circuit specifically includes a resistor R2, one end of which is connected to the input port and the other end is connected to the on-time control interface of the DC chip. The on-time control circuit is used to adjust the on-time; the resistor R2 is the only device for controlling the on-time. By adjusting the resistance value of R2, basically all on-time requirements can be met.

[0024] The ripple feedback circuit specifically includes resistor R3, capacitor C2, and capacitor C6, which are used to adjust the output port ripple and control the output voltage. The ripple measured by an oscilloscope is greater than the trigger value of 25mV to ensure the output validity.

[0025] The voltage feedback circuit specifically includes resistors R4 and R6. Voltage feedback is performed through the midpoint of the two resistors to adjust the output voltage. By adjusting the ratio of R4 and R6, the feedback voltage from the midpoint to the DC chip is changed, and the output voltage value is changed to ensure that the output voltage is within a controllable range. The output mutual inductance circuit is controlled by transformer T1. By changing the turns ratio and magnetic ring parameters of T1, the secondary side output voltage value and the limiting current size can be adjusted to ensure the control of the secondary side power and the design of the power supply parameters. At the same time, the two power supplies can also be isolated to provide isolation conditions for some systems.

[0026] The output mutual inductance circuit is specifically a mutual inductance transformer, the input end of the mutual inductance transformer is connected to the first output port, and the output end of the mutual inductance transformer is connected to the second output port; a diode D1 is connected in series to the output end of the output mutual inductance circuit to ensure the direction of the secondary current loop and to adjust the current direction at the same time.

[0027] The output filter circuit specifically includes capacitors C3 and C4 connected in parallel. The output filter circuit is used to filter out the ripple of the second output port, improve the stability of the input and output voltages, and reduce the interference of the ripple on the subsequent system.

[0028] In a specific embodiment, the resistors R1, R2, R3, R4, R5, and R6 are all resistors that can be quickly replaced and can be set according to actual needs.

[0029] Compared with the existing dual-channel DC power supply design, the dual-channel DC power supply design with constant on-time in the embodiment of the present application has a relatively simple circuit and reduces the cost; the input protection and ripple feedback circuit improves the safety and stability of the system; the output mutual inductance circuit increases the flexibility of system design and improves compatibility; and it is suitable for electronic system design scenarios of general complexity.

[0030] The dual-channel DC power supply design with constant on-time in the embodiment of this patent was designed, manufactured and experimentally tested. The experimental results show that the dual-channel DC power supply design with constant on-time provided by this patent has an input voltage range of 7.5 to 100V and a conversion efficiency of up to 84%. The PCB design area can be reduced by 30% compared to the traditional dual-channel DC power supply, and the cost is only 60%.

[0031] This patent uses specific embodiments to illustrate the principles and implementation methods of this patent. The description of the above embodiments is only used to help understand the methods and core ideas of this patent. At the same time, for ordinary technicians in this field, based on the ideas of this patent, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on this patent.

Claims

1. A dual-circuit DC power supply with a constant on-time, characterized in that: It includes a DC chip, an input filter circuit, an input protection circuit, an input port, a conduction time control circuit, a ripple feedback circuit, a voltage feedback circuit, an output mutual inductance circuit, an output filter circuit, a first output port, and a second output port. The DC chip includes an input end, a conduction time control interface, a voltage feedback circuit output interface, a voltage feedback circuit feedback interface, a ripple feedback circuit output interface, a ripple feedback circuit feedback interface, and an output interface. The three interfaces of the input end of the DC chip are independently connected to the input filter circuit output end, the input protection circuit output end, and the input port. The conduction time control interface of the DC chip is connected to the conduction time control interface. The control circuit is connected between the voltage feedback circuit output interface of the DC chip and the input end of the voltage feedback circuit, the feedback end of the voltage feedback circuit is connected to the voltage feedback circuit feedback interface of the DC chip, the ripple feedback circuit output interface of the DC chip is connected to the input end of the ripple feedback circuit, the feedback end of the ripple feedback circuit is connected to the ripple feedback circuit feedback interface of the DC chip, one of the output interfaces of the DC chip is directly connected to the first output port, the other output interface of the DC chip is connected to the output mutual inductance circuit and then to the second output port, and the second output port is also externally connected to the output filter circuit; One end of the input filter circuit is connected to the input port and the other end is grounded, so as to filter out the ripple of the input voltage; The input protection circuit specifically includes a resistor R1 and a resistor R5, the two resistors are connected by a connecting line, the midpoint of the connecting line of the two resistors is connected to the corresponding interface of the input end of the DC chip, one end of the input protection circuit is connected to the input port, and the other end is grounded, and the input protection circuit is used to adjust the power supply on and off according to the input voltage; The on-time control circuit specifically includes a resistor R2, one end of the on-time control circuit is connected to the input port, and the other end is connected to the on-time control interface of the DC chip, and the on-time control circuit is used to adjust the on-time; The ripple feedback circuit specifically includes a resistor R3, a capacitor C2, and a capacitor C6, which are used to adjust the output port ripple and control the output voltage; The voltage feedback circuit specifically includes a resistor R4 and a resistor R6, and voltage feedback is performed through the midpoint of the two resistors to adjust the output voltage; The output filter circuit specifically includes a capacitor C3 and a capacitor C4 connected in parallel, and the output filter circuit is used to filter out ripples at the output port.

2. A dual-circuit DC power supply with a constant on-time as claimed in claim 1, characterized in that: The output mutual inductance circuit is specifically a mutual inductance transformer, the input end of the mutual inductance transformer is connected to the first output port, and the output end of the mutual inductance transformer is connected to the second output port.

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