Patent ID: 8890441
Filing Date: 2014-11-18
Classification: H02M,H05B

Abstract:
1. A load driving device, comprising: a switch for performing switching control of an output current flowing through a load; a driver that performs on/off control of the switch in accordance with a switch control signal; a comparator that compares a current detection voltage corresponding to a sense current flowing through the switch with a current peak setting voltage, and based on a result of the comparison, generates a current peak detection signal; an AD converter that converts the current detection voltage into a current detection signal; a DA converter that converts a current peak setting signal into the current peak setting voltage; and a logic portion that, upon receiving inputs of the current peak detection signal and the current detection signal, outputs the switch control signal and the current peak setting signal, wherein the logic portion includes a computation circuit that calculates a signal value of the current peak setting signal by using a computation equation expressed by Y1=AVE×α+Δ×Ton/2, where a signal value of the current peak setting signal is denoted as Y1, an average current set value of the output current as AVE, an adjustment coefficient for the average current set value as α, an on period of the switch as Ton, and a change rate of the current detection signal in the on period of the switch as Δ, and the computation circuit determines the adjustment coefficient in accordance with a computation mode setting signal.