| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an LED drive circuit that can output a certain level of pulse current to an LED even if an LED dimming switch turns on and off with a high frequency. <P>SOLUTION: The LED drive circuit comprises: a voltage conversion unit 1 converting input voltage to the other voltage; a first LED group of LED1 to LEDn made up of a plurality of LEDs connected in series; a switching element Q1 that switches according to an LED dimming signal to interrupt the other voltage applied from the voltage conversion unit to the first LED group; a PWM modulation unit 2 that performs a PWM modulation of a reference voltage corresponding to a pulse peak value of LED current flowing through the first LED group by the use of the LED dimming signal; a first averaging unit 3 averaging voltage corresponding to the LED current; a second averaging unit 4 averaging voltage performed the PWM modulation in the PWM modulation unit; and a controlling unit 6 that controls the other voltage applied to the first LED group based on the voltage averaged in the first averaging unit and the voltage averaged in the second averaging unit. <P>COPYRIGHT: (C)2012,JPO&INPIT |
