DC/DC converter and television using same

摘要

A DC/DC converter 10 has a high-side transistor QH as a switching element and a low-side transistor QL as a synchronous rectifier element. A first primary electrode D and secondary primary electrode S of the high-side transistor QH are connected to an input voltage VIN and an external terminal T1, respectively. A detection transistor QD is provided in a row with the high-side transistor QH, and the ON voltage of the high-side transistor QH when ON is output as detection voltage VQD from the detection transistor QD. The output detection voltage VQD is added to a feedback voltage VFB1 by an adder CB, and inputted to a comparator CMP1. The ON period of a one-shot pulse PS1 outputted from the comparator CMP1 is regulated so as to be in direct proportion to the sum of the detection voltage VQD and the feedback voltage VFB1.

主权项

1. A DC/DC converter comprising:
an input voltage; an output terminal for converting the input voltage and outputting an output voltage; an inductor connected to the output terminal; a switching element having a first primary electrode connected to the input voltage and a second primary electrode connected to the output terminal in order for energy to be supplied to the inductor; an output capacitor for smoothing the energy accumulated within the inductor, and for outputting the output voltage; a feedback voltage generating circuit for feeding back to the switching element the output voltage generated in the output capacitor; and an adder for adding the ON voltage of the switching element when ON and the feedback voltage generated in the feedback voltage generating circuit, wherein the ON voltage when the switching element is ON is outputted from an ON voltage detection transistor connected in parallel with the switching element.