CN202032520U - Light-emitting diode (LED) lighting lamp circuit for refrigerator - Google Patents

Abstract

The utility model provides an LED lighting circuit for a refrigerator. An external power supply is connected to a resistance-capacity step-down circuit and a rectification and filtering circuit through a switch. The rectification and filtering circuit is connected to an LED light emitting circuit, and the LED light emitting circuit is connected in parallel with a voltage-stabilizing diode circuit. , the zener diode circuit is connected in series with a current limiting resistor. When the grid voltage and grid frequency fluctuate, or the door switch K1 contacts vibrate due to fast opening and closing of the door, or the door switch K1 contact itself is not in good contact, the residual voltage on the C1 capacitor and the large current generated by the superposition of the grid voltage will pass through Z1 and The current-limiting resistor R6, due to the existence of the current-limiting resistor R6, can avoid the over-current breakdown of the Zener diode Z1 or the over-current burning of the resistor R1 or R2.

Description

LED lighting circuit for refrigerator

technical field

The utility model relates to the technical field of lighting circuits, in particular to an LED lighting circuit used inside a refrigerator.

Background technique

Existing conventional LED lights for refrigerators, see attached figure 1, K1 in the circuit is a door switch, R1, R3 are current limiting resistors, C1 is a step-down capacitor, R2 is the discharge resistor of C1, D1, D2, D3, D4 Is a rectifier diode, Z1 is a Zener diode, C2 is a filter capacitor, LED1, LED2, LED3, LED4 are light-emitting diodes, R4, R5 are light-emitting diode current-limiting resistors. The circuit is externally connected to the mains voltage of 220V AC. Generally, the resistance-capacitance step-down is used to provide power to the LED light-emitting diodes after rectification, filtering and stabilization. However, in the actual use of this circuit, the grid voltage and grid frequency fluctuate. When the contact of the door switch K1 shakes or the contact of the door switch K1 itself is not in good contact, the residual voltage on the C1 capacitor and the grid voltage superimpose, resulting in overcurrent breakdown of the Zener diode Z1 or overcurrent burnout of the resistor R1 or R2.

Contents of the invention

The technical problem to be solved by the utility model is to overcome the existing problems in the prior art, provide an improved resistance-capacitance step-down circuit for LED lighting lamps for refrigerators, and improve circuit reliability with minimal cost increase. the

In order to solve the problems referred to above, the technical scheme of the utility model is as follows:

An LED lighting circuit for a refrigerator. An external power supply is connected to a resistance-capacity step-down circuit and a rectification and filtering circuit through a switch. The rectification and filtering circuit is connected to an LED light emitting circuit. A current limiting resistor is connected in series with the diode circuit.

The impedance range of the current limiting resistor is 100Ω~1000Ω.

Due to the adoption of the above technical solution, when the grid voltage and grid frequency fluctuate, or the door switch K1 contacts vibrate due to fast opening and closing of the door, or the door switch K1 contact itself is in poor contact, the residual voltage on the C1 capacitor and the grid voltage are superimposed to generate The large current must pass through Z1 and the current limiting resistor R6. Due to the existence of the current limiting resistor R6, the overcurrent breakdown of the Zener diode Z1 or the overcurrent burning of the resistor R1 or R2 can be avoided.

Description of drawings

Fig. 1 is a schematic diagram of an LED lighting circuit in the prior art.

Fig. 2 is the LED lighting circuit schematic diagram described in the utility model.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the utility model easy to understand, the utility model will be further elaborated below in conjunction with specific illustrations.

Referring to Figure 2, in the circuit, K1 is a gate switch, R1 and R3 are current limiting resistors, C1 is a step-down capacitor, R2 is a discharge resistor of C1, D1, D2, D3, D4 are rectifier diodes, Z1 is a Zener diode, C2 are filter capacitors, LED1, LED2, LED3, and LED4 are light-emitting diodes, R4 and R5 are light-emitting diode current-limiting resistors, and current-limiting resistor R6 is added to the Zener diode Z1 branch. The impedance range of R6 resistor is 100Ω~1000Ω. The door switch K1 is connected to the 220V circuit. The door switch K1 is connected in series with resistors R1 and R2, and the resistor R2 is connected in parallel with the step-down capacitor C1. Then the circuit is connected in series with a rectifier circuit composed of rectifier diodes D1, D2, D3, and D4. The rectifier circuit is connected in series with resistors R3 is then connected to LED1, LED2, LED3 and LED4 in the light-emitting diode circuit, and the filter capacitor C2 is connected in parallel at both ends of the diode circuit. Zener diode Z1 and current limiting resistor R6 are connected in parallel to both ends of the diode circuit after being connected in series. The light emitting diodes LED1, LED2 are connected in series with the resistor R4, and the light emitting diodes LED3, LED4 are connected in series with the resistor R5.

When the grid voltage and grid frequency fluctuate, or the door switch K1 contacts vibrate due to fast opening and closing of the door, or the door switch K1 contact itself is not in good contact, the residual voltage on the C1 capacitor and the grid voltage superimpose a large current to pass through Z1 and The current-limiting resistor R6, due to the existence of the current-limiting resistor R6, can avoid the over-current breakdown of the Zener diode Z1 or the over-current burning of the resistor R1 or R2.

The basic principles, main features and advantages of the present utility model have been shown and described above. Those skilled in the industry should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. The utility model does not depart from the spirit and scope of the utility model There will also be various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (2)

1. refrigerator LED lighting lamp circuit, external power supply connects a resistance-capacitance depressurization circuit and a current rectifying and wave filtering circuit by a switch, current rectifying and wave filtering circuit connects LED lamp illuminating circuit, LED lamp illuminating circuit is parallel with a diode circuit of voltage regulation, it is characterized in that this diode circuit of voltage regulation is in series with a current-limiting resistance.

2. a kind of refrigerator LED lighting lamp circuit according to claim 1 is characterized in that, the current-limiting resistance impedance ranges is 100 Ω ~ 1000 Ω.

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