基于PS92010設計的高效PWM LED驅動方案
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離線LED照明驅動模塊TPS92010EVM-592
TPS92010 High Efficiency Offline LED Lighting Driver Controller Evaluation Module
The TPS92010EVM-592 is a TRIAC dimmable LED driver. It can provide a 0.325-A constant current to four or five high-brightness LEDs. The EVM includes a five-LED load. It is powered from the mains which is rated at 100 Vrms to 130 Vrms. The output current can be modified for constant levels from 0.2 A to 0.7 A.
This EVM uses the TPS92010 high efficiency offline LED lighting driver controller. The power topology is a quasi resonant mode flyback. This makes for a cost competitive solution. This TPS92010 EVM implements a constant current, high efficiency, low ripple AC-DC LED lighting driver.
Current is sensed directly via a resistor and operational-amplifier. This in turn drives an opto-coupler which sets the PWM pulses via the TPS92010 to control the output current at a constant level.The design also incorporates a circuit to ensure compatibility with a large number of commonly available TRIAC based dimmers. This circuit monitors the line voltage for TRIAC operation. When the TRIAC is operating the line voltage is chopped. This information is used by the circuit to reduce the constant output current level thus dimming the LEDs. It also applies a current path at the input to ensure the TRIAC triggers correctly and maintains triggered condition.
離線LED照明驅動模TPS92010EVM-592塊主要特性：
TRIAC compatible dimming
Low-cost line powered LED driver solution
Includes 5 HB-LEDs as a sample load
Allows easy use of user own LED load
Test points for LED voltage and current
Accurate current sensing to maintain constant current to LEDs
Modifiable output current from 0.2 A to 0.7 A, 0.325 A is default
圖５．TPS92010EVM-592 PSU (HPA594)電路圖
TPS92010EVM-592材料清單（BOM）：
pwm相關文章:pwm原理
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