Patent ID: 7737773
Filing Date: 2010-06-15
Classification: H02M,H03K

Abstract:
1. A semiconductor device comprising: a first switching element connected in series between a terminal to which an input voltage is applied and a leader terminal of an output voltage; a constant voltage circuit that generates a desired constant voltage from the input voltage with reference to a ground voltage; a bootstrap circuit that receives the constant voltage and generates a boot voltage that is higher than the output voltage; a first logic generating circuit that generates a first logic signal for performing control of turning on and off the first switching element; and a first drive circuit that performs control of turning on and off the first switching element by using the boot voltage based on the first logic signal, wherein the bootstrap circuit includes an LDMOS transistor having a source connected to an output terminal of the constant voltage circuit and a drain connected to a leader terminal of the boot voltage, and a bootstrap control circuit that performs control of turning on and off the LDMOS transistor, and wherein the bootstrap control circuit controls a back gate of the LDMOS transistor so as to control of turning on and off the LDMOS transistor.