CN201332523Y - LED step-down drive circuit absorbing surge - Google Patents

Abstract

A LED step-down drive circuit absorbing surge, wherein current is commutated by using capacitance step-down via commutation circuit, then is wave-filtered into DC via a wave filter capacitance, the surge current of the DC is absorbed via an surge limit capacitance series voltage regulator such as constant voltage diode, then both ends of the constant voltage diode connects with a LED lamp after limit capacitance. The LED lamp is a constant voltage element, voltage is constant, the circuit steps-down via a capacitance, in steady-state, working current is determined with size of the capacitance of, addition of voltage drop through the LED limit resistance of max working current and voltage of the LED is designed to not higher than steady voltage of the voltage regulator, thereby confirming the voltage regulator does not work in steady-state and reducing power consumption in steady-state. The utility model prevents step-down surge current from damaging LED elements, conserves low consumption of capacitance step-down, provides simple and practical circuit, saves energy comparing with present resistance-capacitance of LED lamps, is simpler and more reliable than switch power drive LED lamps without high-frequency interference.

Description

A surge-absorbing LED capacitor step-down driving circuit

[technical field]

The utility model relates to a surge-absorbing LED capacitor step-down driving circuit.

[Background technique]

In the known LED capacitor step-down drive circuit, in order to prevent the surge current from damaging the LED lamp, a resistor is connected in series to limit the surge current when inputting. This not only consumes a lot of power, but also because the surge voltage is large, although the resistance value Larger, but the surge current is still very large, and some rectifiers are first stabilized and then stabilized to drive LED lights, which not only complicates the circuit but also consumes a lot of power, so most LED drive circuits are made of integrated circuits. switching power supply.

[utility model content]

The utility model first uses a capacitor to step down the voltage and rectify it through a rectifier circuit, and then filter it into a direct current through a filter capacitor. The inrush current is very large, and a high-power Zener tube can be selected. Their transient operating current is large, so that the surge current limiting resistor can be used smaller, and the steady-state power consumption is also smaller. Then, the two ends of the tube Connect the LED lamp through the current-limiting resistor. The LED lamp is a constant voltage element, and the voltage is constant. This circuit is stepped down by a capacitor. In a steady state, the working current is mainly determined by the size of the capacitor. The maximum working The voltage drop of the current flowing through the LED current-limiting resistor, plus the voltage of the LED lamp is designed to be no greater than the stable voltage of the voltage regulator device, which ensures that the voltage regulator device does not work in the steady state, which also reduces the steady-state power consumption.

It can be seen from the above that the utility model not only effectively solves the damage of the surge current to the LED element, but also retains the low power consumption of the capacitor step-down. The circuit is relatively simple and has obvious practicability.

[Description of drawings]

The accompanying drawings describe in detail the content of the present utility model.

Fig. 1 is a schematic block diagram of the utility model. The AC power supply can be AC mains voltage stepped down by the step-down capacitor C1(1), input to the rectifier circuit (2), the output of the rectifier circuit is filtered by the filter capacitor C(2) into DC, and then passed through the surge current limiting resistor R1( 4) The semiconductor device D (5) with voltage stabilizing characteristics is connected in series to absorb the surge current, and the LED lamp (7) with LED current limiting resistor R2 (6) is connected in series to the two ends of the voltage stabilizing device D. The voltage stabilizing device The stable voltage of D is not greater than the sum of the maximum voltage drop of the LED current-limiting resistor and the LED lamp in the steady state, so that the power consumption of the regulator tube in the steady state is small when the voltage regulator tube is not working. When the dielectric resistance of C1 is large, in order to To speed up the discharge when the power is off, an appropriate resistor can be connected in parallel at the two terminals of C1.

Fig. 2 is an electrical schematic diagram of the utility model, wherein the rectifier circuit (2) is a bridge rectifier circuit composed of D1, D2, D3, and D4, and the LED lamp is composed of 3 LED tubes connected in series into a group of 3 groups in parallel the lights.

Figure 3 is another electrical schematic diagram of the utility model, wherein the rectifier circuit (2) is a half-wave voltage doubler rectifier circuit composed of D5 and D6, and the LED lamp is a lamp composed of 3 LED tubes connected in series..

[Detailed ways]

The following embodiments are described in conjunction with the accompanying drawings.

Fig. 2 is an embodiment of the present utility model, and C1 is 1 μ f capacitor, and D1, D2, D3, D4 are diode 4007, and C2 is 100 μ f capacitor, and R1 is 100 Ω resistance, and D is 15V/1W regulator tube, and R2 is 68 Ω Resistors, 9 LED light-emitting diodes are all low-power light-emitting diodes, it is a very practical light.

Fig. 2 is another embodiment of the utility model, which is used when the LED lamp current is small, C1 is a 0.68μf capacitor, D5 and D6 are diodes 4007, C2 is a 100μf capacitor, R1 is a 100Ω resistor, and D is 15V/ 1W regulator tube, R2 is a 200Ω resistor, and the three LED light-emitting diodes are all low-power light-emitting diodes, forming a small night light.

To sum up, the utility model effectively solves the damage to the LED element caused by the capacitor step-down surge current, retains the low power consumption of the capacitor step-down, the circuit is simple and practical, and is reliable and energy-saving compared with the known RC-step-down LED lamp , Simpler and more reliable than switching power supply to drive LED lights, without high frequency interference.

Claims (5)

1, a kind of LED capacitance decompression drive circuit that absorbs surge, it is characterized in that comprising decompression capacitor C1 (1), rectification circuit (2), filter capacitor C2 (3), surge current-limiting resistance R1 (4) has the semiconductor device D (5) of stabilized voltage characteristic, LED current-limiting resistance R2 (6), with LED lamp (7), AC power one end is behind C1 (1), and two ends connect the input of rectification circuit (2) simultaneously, and it is exported two ends and meets C2 (3), after the termination R1 (4) of C2 is connected in series D (5) again, the other end that meets C2 is as common port, and D connects the end that R2 (6) is connected in series LED lamp (7) then again with the contact of R1, another termination common port of LED lamp.

2, according to claim 1, a kind of LED capacitance decompression drive circuit that absorbs surge is characterized in that described surge current-limiting resistance R1 (4), should be limited within the working range of the semiconductor device D (5) with stabilized voltage characteristic greatly to making decompression capacitor C1 (1) go up the surge current that produces.

3, according to claim 1, a kind of LED capacitance decompression drive circuit that absorbs surge is characterized in that described semiconductor device D (5) with stabilized voltage characteristic, and its burning voltage should be not less than LED current-limiting resistance R2 (6) and LED lamp (7) maximum voltage drop sum when stable state.

4 according to claim 1, and a kind of LED capacitance decompression drive circuit that absorbs surge is characterized in that described rectification circuit (2), can be made up of full-wave bridge rectifier circuit or half-wave voltage doubler.，

5, according to claim 1, a kind of LED capacitance decompression drive circuit that absorbs surge is characterized in that described LED lamp (7) can be by single led pipe or the series connection of a plurality of LED pipe, and parallel connection or series-parallel connection are formed.

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