Control circuit for reducing standby power consumption of resonance circuit and power factor correction circuit and liquid crystal display television
By combining LLC resonant circuit and PFC control chip, and utilizing the combination of field-effect transistors, capacitors and resistors, the high power consumption problem of PFC+LLC architecture switching power supply in standby mode is solved, achieving simple, reliable and low-cost standby power consumption reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN CHANGHONG ELECTRIC CO LTD
- Filing Date
- 2025-04-29
- Publication Date
- 2026-05-05
AI Technical Summary
Existing PFC+LLC architecture switching power supplies have high power consumption in standby mode. Existing control methods are complex and costly, making it difficult to effectively reduce standby power consumption.
A simple circuit structure is adopted, which combines LLC resonant circuit and PFC control chip, and uses field-effect transistors, capacitors and resistors to control LLC resonant circuit and PFC circuit, thereby reducing standby power consumption.
A simple and reliable circuit structure was achieved, which effectively reduced the standby power consumption of the PFC+LLC architecture switching power supply. It is low in cost and highly feasible.
Smart Images
Figure CN224205139U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power electronics technology, and in particular to a control circuit for reducing standby power consumption using a resonant circuit and a power factor correction circuit, as well as an LCD TV. Background Technology
[0002] With the rapid development of the flat-panel TV industry, TVs are becoming larger and more feature-rich, and the overall power consumption is also increasing. More and more flat-panel TVs are adopting high-power switching power supplies, especially PFC (Power Factor Correction Circuit) + LLC (Resonant Circuit) architecture switching power supplies.
[0003] However, with the rapid development of the Internet of Things and smart homes, more and more TV users are choosing to leave their TVs in standby mode when not in use, meaning they don't leave the AC power on. While this brings convenience, it also inadvertently increases the TV's power consumption. For example, a 5W LCD TV in standby mode consumes approximately 43.8 kWh over 365 days, resulting in significant electricity costs and substantial energy waste.
[0004] According to China's energy efficiency standards, the standby power consumption of flat-screen TVs manufactured after January 1, 2012, must not exceed 0.5W. Typically, TV systems reduce standby power consumption by turning off unnecessary peripherals or ports; however, the switching power supply itself also consumes power under standby conditions. PFC (Power Factor Correction) + LLC (Resonant Circuit) architecture switching power supplies, due to their unique operating mode, can even experience instantaneous power consumption of 2-5W.
[0005] To reduce the standby power consumption of PFC+LLC architecture switching power supplies, the industry commonly uses a standby signal generated by the motherboard, which is then used by a control circuit composed of a switching circuit and an optocoupler to further control the PFC circuit to turn on or off. However, this control method is relatively complex and also incurs certain material costs.
[0006] Therefore, whether there is a better way to reduce the standby power consumption of PFC (Power Factor Correction) + LLC (Resonant Circuit) architecture switching power supplies is an urgent problem that needs to be considered and solved. Utility Model Content
[0007] To address the problems existing in the prior art, the purpose of this utility model is to provide a control circuit and LCD TV that reduces standby power consumption using a resonant circuit and a power factor correction circuit. This utility model has a simple circuit structure, low cost, and strong feasibility.
[0008] To achieve the above objectives, the technical solution adopted by this utility model is: a control circuit for reducing standby power consumption using a resonant circuit and a power factor correction circuit, comprising an LLC resonant circuit, a first integrated circuit, and a second integrated circuit; the LLC resonant circuit is connected to the seventh pin of the first integrated circuit through a second capacitor, a fourth capacitor is provided between the sixth and twelfth pins of the first integrated circuit, and the third pin of the first integrated circuit is connected to the second integrated circuit through a third field-effect transistor.
[0009] As a further improvement of this utility model, the LLC resonant circuit includes a transformer T, a first field-effect transistor (FET), and a second FET. The second pin of the first FET is connected to the positive terminal of the bus capacitor, the first pin of the first FET is connected to the fifteenth pin of the first integrated circuit, and the third pin of the first FET is simultaneously connected to the second pin of the second FET, the fourteenth pin of the first integrated circuit, and the fourth pin of the transformer. The first pin of the second FET is connected to the eleventh pin of the first integrated circuit, and the third pin of the second FET is connected to the negative terminal of the bus capacitor. A first capacitor is connected across the third pin of the transformer and the negative terminal of the bus capacitor.
[0010] As a further improvement of this utility model, a first resistor is connected between the first pin of the first field-effect transistor and the fifteenth pin of the first integrated circuit, and a second resistor is connected between the first pin of the second field-effect transistor and the eleventh pin of the first integrated circuit.
[0011] As a further improvement of this utility model, the first pin of the second capacitor is connected to the third pin of the transformer, the second pin of the second capacitor is simultaneously connected to the first pin of the third resistor and the first pin of the fourth resistor, the second pin of the third resistor is connected to the hot ground, the second pin of the fourth resistor is connected to the seventh pin of the first integrated circuit, and a third capacitor is connected between the seventh pin of the first integrated circuit and the hot ground.
[0012] As a further improvement of this utility model, a fifth capacitor is connected between the third pin of the first integrated circuit and the hot ground; the third pin of the first integrated circuit is connected to the first pin of the fifth resistor; the second pin of the fifth resistor is connected to the first pin of the third field-effect transistor; a sixth capacitor is connected between the first pin of the third field-effect transistor and the hot ground; the third pin of the third field-effect transistor is connected to the third pin of the second integrated circuit; the second pin of the third field-effect transistor is connected to the hot ground; and a seventh capacitor is connected between the third pin of the second integrated circuit and the hot ground.
[0013] As a further improvement of this utility model, the first integrated circuit is an LLC control chip, and the second integrated circuit is a PFC control chip.
[0014] This utility model also discloses an LCD TV, including the resonant circuit and power factor correction circuit described above, and a control circuit to reduce standby power consumption.
[0015] The beneficial effects of this utility model are:
[0016] This invention uses a simple circuit structure to form a simple and reliable control circuit, which can effectively reduce the standby power consumption of PFC+LLC architecture switching power supplies. The circuit structure is simple, the cost is low, and the implementation is strong. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the resonant circuit in an embodiment of the present invention;
[0018] Figure 2 This is a schematic diagram of the circuit structure of the first integrated circuit and the second integrated circuit in an embodiment of this utility model. Detailed Implementation
[0019] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0020] Example
[0021] like Figure 1 and Figure 2 As shown, a control circuit for reducing standby power consumption using a resonant circuit and a power factor correction circuit includes a transformer T1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, a first field-effect transistor Q1, a second field-effect transistor Q2, a third field-effect transistor Q3, a first integrated circuit U1 (LLC control chip), and a second integrated circuit U2 (PFC control chip).
[0022] In this configuration, the second pin of the first field-effect transistor Q1 is connected to the positive terminal (V-bulk) of the bus capacitor. The first resistor R1 is connected between the fifteenth pin of the first integrated circuit U1 and the first pin of the first field-effect transistor Q1. The second resistor R2 is connected between the eleventh pin of the first integrated circuit U1 and the first pin of the second field-effect transistor Q2. The third pin of the first field-effect transistor Q1 is simultaneously connected to the second pin of the second field-effect transistor Q2, the fourteenth pin of the first integrated circuit U1, and the fourth pin of the transformer T1. The third pin of the second field-effect transistor Q2 is connected to the negative terminal (hot ground) of the bus capacitor. The first capacitor C1 is connected between the third pin of the transformer T1 and the negative terminal (hot ground) of the bus capacitor. The first pin of the second capacitor C2 is connected to the third pin of the transformer T1. The second pin of the second capacitor C2 is simultaneously connected to the first pin of the third resistor R3 and the first pin of the fourth resistor R4. The second pin of the third resistor R3 is connected to hot ground. The second pin of the fourth resistor R4 is connected to the seventh pin of the first integrated circuit U1. The third capacitor C3 is connected between the seventh pin of the first integrated circuit U1 and hot ground.
[0023] The above circuits constitute a typical LLC resonant circuit.
[0024] The fourth capacitor C4 is connected between the sixth pin of the first integrated circuit U1 and the hot ground. The fifth capacitor C5 is connected between the third pin of the first integrated circuit U1 and the hot ground. The first pin of the fifth resistor R5 is connected to the third pin of the first integrated circuit U1, and the second pin of the fifth resistor R5 is connected to the first pin of the third field-effect transistor Q3. The sixth capacitor C6 is connected between the first pin of the third field-effect transistor Q3 and the hot ground. The third pin of the third field-effect transistor Q3 is connected to the third pin of the second integrated circuit U2, and the second pin of the third field-effect transistor Q3 is connected to the hot ground. The seventh capacitor C7 is connected between the third pin of the second integrated circuit U2 and the hot ground.
[0025] Figure 2 The main working principle of the circuit is as follows:
[0026] The second capacitor C2 is used to detect the input power of the LLC resonant circuit and generate a corresponding detection signal, which is then transmitted to pin 7 of the first integrated circuit U1 through the fourth resistor R4. The third capacitor C3 is used to filter out interference and noise from pin 7 of the first integrated circuit U1 (LLC control chip). When the first integrated circuit U1 (LLC control chip) receives the detection signal, the fourth capacitor C4 generates a corresponding voltage signal, which is transmitted to pin 3 of the first integrated circuit U1 (LLC control chip) through its internal circuitry. Pin 3 of the first integrated circuit U1 generates a corresponding control level, which is then current-limited by the fifth resistor R5 and transmitted to pin 1 of the third field-effect transistor Q3. The third field-effect transistor Q3 performs an on / off operation based on the control level generated by pin 3 of the first integrated circuit U1, thereby controlling pin 3 of the second integrated circuit U2 (PFC control chip).
[0027] When the input power of the LLC resonant circuit is above the set threshold, the third pin of the first integrated circuit U1 (LLC control chip) generates a low level, the third field-effect transistor Q3 is turned off, and the second integrated circuit U2 (PFC control chip) works normally.
[0028] When the input power of the LLC resonant circuit is below the set threshold, the third pin of the first integrated circuit U1 (LLC control chip) generates a periodic high and low level, the third field-effect transistor Q3 is periodically turned on and off, and the third pin of the second integrated circuit U2 (PFC control chip) is periodically pulled low to hot ground. The second integrated circuit U2 (PFC control chip) enters the intermittent oscillation working mode, ultimately achieving the purpose of reducing standby power consumption.
[0029] This embodiment also discloses a liquid crystal television, including a resonant circuit and a power factor correction circuit as described above, and a control circuit for reducing standby power consumption.
[0030] The embodiments described above merely illustrate specific implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.
Claims
1. A control circuit for reducing standby power consumption using a resonant circuit and a power factor correction circuit, characterized in that, It includes an LLC resonant circuit, a first integrated circuit, and a second integrated circuit; the LLC resonant circuit is connected to the seventh pin of the first integrated circuit through a second capacitor, a fourth capacitor is provided between the sixth and twelfth pins of the first integrated circuit, and the third pin of the first integrated circuit is connected to the second integrated circuit through a third field-effect transistor.
2. The control circuit for reducing standby power consumption using the resonant circuit and power factor correction circuit according to claim 1, characterized in that, The LLC resonant circuit includes a transformer T, a first field-effect transistor (FET), and a second FET. The second pin of the first FET is connected to the positive terminal of the bus capacitor, and the first pin of the first FET is connected to the fifteenth pin of the first integrated circuit. The third pin of the first FET is simultaneously connected to the second pin of the second FET, the fourteenth pin of the first integrated circuit, and the fourth pin of the transformer. The first pin of the second FET is connected to the eleventh pin of the first integrated circuit, and the third pin of the second FET is connected to the negative terminal of the bus capacitor. A first capacitor is connected across the third pin of the transformer and the negative terminal of the bus capacitor.
3. The control circuit for reducing standby power consumption using the resonant circuit and power factor correction circuit according to claim 2, characterized in that, A first resistor is connected between the first pin of the first field-effect transistor and the fifteenth pin of the first integrated circuit, and a second resistor is connected between the first pin of the second field-effect transistor and the eleventh pin of the first integrated circuit.
4. The control circuit for reducing standby power consumption using the resonant circuit and power factor correction circuit according to claim 1, characterized in that, The first pin of the second capacitor is connected to the third pin of the transformer. The second pin of the second capacitor is simultaneously connected to the first pin of the third resistor and the first pin of the fourth resistor. The second pin of the third resistor is connected to the hot ground. The second pin of the fourth resistor is connected to the seventh pin of the first integrated circuit. A third capacitor is connected between the seventh pin of the first integrated circuit and the hot ground.
5. The control circuit for reducing standby power consumption using the resonant circuit and power factor correction circuit according to claim 1, characterized in that, A fifth capacitor is connected between the third pin of the first integrated circuit and the hot ground. The third pin of the first integrated circuit is connected to the first pin of the fifth resistor. The second pin of the fifth resistor is connected to the first pin of the third field-effect transistor. A sixth capacitor is connected between the first pin of the third field-effect transistor and the hot ground. The third pin of the third field-effect transistor is connected to the third pin of the second integrated circuit. The second pin of the third field-effect transistor is connected to the hot ground. A seventh capacitor is connected between the third pin of the second integrated circuit and the hot ground.
6. The control circuit for reducing standby power consumption according to any one of claims 1-5, characterized in that, The first integrated circuit is an LLC control chip, and the second integrated circuit is a PFC control chip.
7. A liquid crystal television, characterized in that, The control circuit for reducing standby power consumption includes the resonant circuit and power factor correction circuit as described in any one of claims 1-6.