On-chip Current Sensing Technique for H-bridge Driver System

On-chip current sensing technique which is one of the most important functions on smart driver chip. Conventional current sensing methods insert a resistor in the path of the current to be sensed. This method incurs significant power losses, especially when the current to be sensed is high. H-bridge MOSFET drivers is a common driving method. Especially in audio and TEC driver system, H-bridge driver is the most used circuit structure to improve the power efficiency. In this paper, a high accuracy and wide current sensing range on chip current sensing technique for H-bridge driver system is presented. The high side driver and low side driver are implemented a closed loop control with operational amplifier respectively to achieve high accuracy. This current sensing technique can sense the current bidirectionally and convert it into voltage signal with a TIA circuit, which is convenient for on-chip or off-chip measurement.