Texas Instruments Corporation

Chao-Chih Chiu

Taylor R Efland

Fernando D Carvajal

Dale J Skelton

David D Briggs

A DC-DC converter that generates a sense signal representing a voltage drop across a low-side switch when the low-side switch is on. The sense signal is inverted and stored in a 'hold' capacitor until the beginning of the next switching cycle. More specifically, an input node receives an input voltage V.sub.IN. A driver stage coupled to the input node and to a reference node chops V.sub.IN into a square wave under control of a PWM signal. The chopped V.sub.IN signal is coupled to an intermediate output node. An output stage coupled to the intermediate output node converts the chopped V.sub.IN signal to an output voltage V.sub.OUT to a load coupled to an output node. A sense unit coupled to sense a voltage on the intermediate output node generates a voltage signal indicating current flowing in the load.

Sensing of current in a synchronous-buck power stage

The invention is a multiplex circuit for outputing two or more signals of different levels to a common output pad where a first output driver (D.sub.h) is powered from a voltage rail having a higher voltage than at least one second output driver (D.sub.1) power by a lower voltage rail. An interface circuit (IFC) and level shift circuit provides two output signals base on a single input signal, one signal being equivalent to the voltage of the higher voltage (V.sub.High) and the other being based on the lower voltage (V.sub.low). PMOS device connected to the output pad has its back gate connected to V.sub.high to prevent leakage current through the PMOS device when the output to the output pad (P.sub.1) is equivalent to V.sub.High.

Growing community of inventors

Taipei, Taiwan

Chao-Chih Chiu