Adjusting the feedback signal improves the efficiency in this buck-converter driver for high-brightness LEDs

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Other Materials from the Main Document

• Article «LED drivers minimize power dissipation»
• Figure 1. A generic buck converter, IC₁, provides constant-current drive for a high- brightness LED
• Figure 2. An op amp, IC₂, increases the LED-current error signal and reduces power dissipation in the sense resistor
• Figure 3. Adjusting the feedback signal improves the efficiency in this buck-converter driver for high-brightness LEDs
• Figure 4. This graph shows LED current as a function of input voltage at half- load for the circuit of Figure 3
• Figure 5. This graph shows LED current as a function of input voltage at full load for the circuit of Figure 3
• Figure 6. A comparison of a normal-feedback circuit (Figure 1) and an adjusted- feedback circuit (Figure 3) shows significant improvements in overall efficiency at half-loads and at full loads