Voltage converting LED circuit with switched capacitor network

摘要

A Voltage Converting LED Circuit with Switched Capacitor Network contains a 2-way MOSFET switch that connects a capacitor network to the output of an error amplifier, thereby enabling the error amplifier to resume operation quickly after the off-time segment of a PWM cycle. The switch is controlled synchronously with current sinks controlling brightness and color levels. In a preferred embodiment, multiple serially connected strings of LED's can be controlled simultaneously via one switch.

主权项

1. A circuit comprising:
a DC-DC voltage converter having a first input to receive a DC voltage, a second input to receive a modulating control signal having at least a first state and a second state, and an output to supply a variable output voltage to a load, the DC-DC voltage converter constructed to supply the variable output voltage to the load during the first state and to stop supplying the variable output voltage to the load during the second state; an operational amplifier having a first input to receive a voltage reference, a second input to receive a feedback voltage from the load, and an output; a compensation RC network including at least one resistor and at least one capacitor; and a switch, coupled to the compensation RC network, constructed to receive the modulating control signal, connect the compensation RC network to the output of the operational amplifier during the first state, and disconnect the compensation RC network to the output of the operational amplifier during the second state.