Standby circuit with low cost and low power consumption
Through the low-cost and low-power standby circuit, the combination of transistor Q1 and switch S1 is used to achieve the low-power standby state of the switching power supply, solving the high power consumption and high cost problems caused by multiple MOS tubes in the prior art.
Patent Information
- Application Number
- CN202422408508.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2034-09-30
AI Technical Summary
The standby circuit structure of existing switching power supplies is complex and requires multiple MOS transistors, resulting in high power consumption and cost.
A low-cost, low-power standby circuit is adopted, including a PWM control circuit and a low-power standby circuit. A transistor Q1 and a common switch S1 are used to pull down the FB terminal level of the PWM chip U1 through the optocoupler U2, so that it is turned off and enters the standby state.
A low-power standby function is achieved, while reducing costs and avoiding the use of multiple MOS tubes.
Smart Images
Figure CN223379054U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of power supply circuits, in particular to a low-cost and low-power standby circuit. Background Art
[0002] The structure of the standby circuit of the existing switching power supply is complex, and generally more than two MOS tubes are needed to control the shutdown of the PWM chip to achieve standby mode. The power consumption and cost of the MOS tubes are relatively high. Utility Model Content
[0003] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art and to provide a low-cost and low-power standby circuit.
[0004] According to an embodiment of the present invention, a low-cost, low-power standby circuit includes a power conversion circuit, a PWM control circuit and a low-power standby circuit. The PWM control circuit is electrically connected to the power conversion circuit to control the output of the power conversion circuit. The PWM control circuit includes a PWM chip U1. The low-power standby circuit includes a transistor Q1, an optocoupler U2, a resistor R1, a resistor R2 and a switch S1. One end of the switch S1 is connected to a high level, and the other end of the switch S1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2 respectively through the series resistor R1. The other end of the resistor R2 and the emitter of the transistor Q2 are grounded respectively. The collector of the transistor Q1 is connected to an operating voltage and is electrically connected to the input end of the optocoupler U2. The output end of the optocoupler U2 is electrically connected to the FB end of the PWM chip U1. When the switch S1 is closed, the high level turns on the transistor Q1, and the level of the FB end of the PWM chip U1 is pulled down through the optocoupler U2, so that the PWM chip U1 is turned off to enter the standby state.
[0005] The low-cost, low-power standby circuit according to the embodiment of the present invention has at least the following beneficial effects: the low-power standby circuit has only one transistor Q1 and an ordinary low-cost switch S1. When the switch S1 is closed, the high level turns on the transistor Q1, and the level of the FB terminal of the PWM chip U1 is pulled down by the optocoupler U2, so that the PWM chip U1 is turned off to enter the standby state. When the power needs to be turned on, the switch S1 can be turned off. The standby function can be achieved without multiple MOS tubes, so that the power consumption is low and the cost is reduced.
[0006] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The following is a further description of the specific embodiments of the present invention in conjunction with the accompanying drawings;
[0008] Figure 1This is the schematic diagram of a low-cost, low-power standby circuit. DETAILED DESCRIPTION
[0009] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.
[0010] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.
[0011] In the description of this utility model, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.
[0012] Reference Figure 1The present invention provides a low-cost, low-power standby circuit, including a power conversion circuit 10, a PWM control circuit 20, and a low-power standby circuit 30. The PWM control circuit 20 is electrically connected to the power conversion circuit to control the output of the power conversion circuit 10. The PWM control circuit 20 includes a PWM chip U1. The low-power standby circuit 30 includes a transistor Q1, an optocoupler U2, a resistor R1, a resistor R2, and a switch S1. One end of the switch S1 is connected to a high level, and the other end of the switch S1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2 via the series resistor R1. The other end of the resistor R2 and the emitter of the transistor Q2 are grounded respectively. The collector of the transistor Q1 is connected to a power supply voltage and is electrically connected to the input end of the optocoupler U2. The output end of the optocoupler U2 is electrically connected to the FB end of the PWM chip U1. When the switch S1 is closed, the high level turns on the transistor Q1, and the level of the FB end of the PWM chip U1 is pulled down through the optocoupler U2, causing the PWM chip U1 to be turned off and enter a standby state. The low-power standby circuit 30 only has one transistor Q1 and an ordinary low-cost switch S1. When the switch S1 is closed, the high level turns on the transistor Q1, and the level of the FB terminal of the PWM chip U1 is pulled down by the optocoupler U2, so that the PWM chip U1 is turned off and enters the standby state. When the power needs to be turned on, the switch S1 can be turned off. The standby function can be achieved without multiple MOS tubes, which reduces power consumption and cost.
[0013] In some embodiments, the switch S1 is controlled by an external MCU to switch on and off, and the high level is provided by an external power supply, or the high level can be provided by the output terminal of the power supply circuit.
[0014] In some embodiments, a 5V auxiliary power supply is further included, and an output end of the 5V auxiliary power supply is electrically connected to the collector of the transistor Q1 to supply power to the transistor Q1 to avoid lack of power supply during standby mode.
[0015] The circuit 40 further includes a feedback circuit 40, one end of which is electrically connected to the output end of the power conversion circuit 10 to detect the output DC voltage, and the other end of which is electrically connected to the PWM control circuit 20 to feed back the detected signal. The feedback circuit 40 includes a transistor TL431, a resistor R3, and a resistor R4. One end of the resistor R3 is electrically connected to the output end of the power conversion circuit 10 to collect the output DC voltage, the other end of the resistor R3 is electrically connected to one end of the resistor R4 and the first end of the transistor TL431, respectively, and the other end of the resistor R4 is grounded to the third end of the transistor TL431. Resistors R3 and R4 act as a voltage divider, and the second end of the transistor TL431 is electrically connected to the PWM control circuit 20 to feed back the detected signal. Furthermore, the feedback circuit 40 includes an optocoupler U3, the input end of which is electrically connected to the second end of the transistor TL431, and the output end of the optocoupler U3 is electrically connected to the FB terminal of the PWM chip U1.
[0016] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above preferred embodiments can be freely combined and superimposed.
[0017] The above are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or directly or indirectly applied in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. A low-cost and low-power standby circuit, characterized in that: include: A power conversion circuit (10), a PWM control circuit (20) and a low-power standby circuit (30), wherein the PWM control circuit (20) is electrically connected to the power conversion circuit to control the output of the power conversion circuit (10), the PWM control circuit (20) includes a PWM chip U1, and the low-power standby circuit (30) includes a transistor Q1, an optical coupler U2, a resistor R1, a resistor R2 and a switch S1, one end of the switch S1 is connected to a high level, the other end of the switch S1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2 via the series resistor R1, the other end of the resistor R2 and the emitter of the transistor Q2 are grounded respectively, the collector of the transistor Q1 is connected to a power supply voltage and is electrically connected to the input end of the optical coupler U2, the output end of the optical coupler U2 is electrically connected to the FB end of the PWM chip U1, when the switch S1 is closed, the high level turns on the transistor Q1, and the level of the FB end of the PWM chip U1 is pulled down through the optical coupler U2, so that the PWM chip U1 is turned off to enter the standby state.
2. The low-cost and low-power standby circuit (30) according to claim 1, characterized in that: The switch S1 is controlled to be on or off by an external MCU.
3. The low-cost and low-power standby circuit (30) according to claim 1, characterized in that: The high level is provided by an external power supply.
4. The low-cost and low-power standby circuit (30) according to claim 1, characterized in that: A 5V auxiliary power supply is also included, and an output end of the 5V auxiliary power supply is electrically connected to the collector of the transistor Q1 to supply power to the transistor Q1.
5. The low-cost and low-power standby circuit (30) according to claim 1, characterized in that: It also includes a feedback circuit (40), one end of the feedback circuit (40) is electrically connected to the output end of the power conversion circuit (10) to detect the output DC voltage, and the other end of the feedback circuit (40) is electrically connected to the PWM control circuit (20) to feed back the detected signal.
6. The low-cost and low-power standby circuit (30) according to claim 5, characterized in that: The feedback circuit (40) includes a transistor TL431, a resistor R3, and a resistor R4. One end of the resistor R3 is electrically connected to the output end of the power conversion circuit (10) to collect the output DC voltage. The other end of the resistor R3 is electrically connected to one end of the resistor R4 and the first end of the transistor TL431 respectively. The other end of the resistor R4 and the third end of the transistor TL431 are grounded respectively. The resistor R3 and the resistor R4 play a voltage dividing role. The second end of the transistor TL431 is electrically connected to the PWM control circuit (20) to feed back the detected signal.
7. The low-cost and low-power standby circuit (30) according to claim 6, characterized in that: The feedback circuit (40) comprises an optocoupler U3, wherein the input end of the optocoupler U3 is electrically connected to the second end of the transistor TL431, and the output end of the optocoupler U3 is electrically connected to the FB end of the PWM chip U1.