Patent ID: 8716990
Filing Date: 2014-05-06
Classification: H02M,Y02B

Abstract:
1. A DC-to-DC converter device comprising: a high-side switch; a low-side switch connected to the high-side switch in series; a high-side controller configured to control the high-side switch; and a low-side controller including: a first detector configured to detect a current of the low-side switch; wherein the first detector includes: a first detecting transistor; a first detecting resistor connected across the low-side switch through the first detecting transistor; and a first amplifier configured to amplify a voltage across the first detecting resistor, wherein the first amplifier includes: a pair of current generators; a pair of input transistors configured to amplify the voltage across the first detecting resistor, the pair of input transistors being supplied with constant currents from the pair of the current generators, one of the pair of input transistors being connected to one end of the first detecting resistor through a first resistor, one other of the pair of input transistors being connected to one other end of the first detecting resistor through a second resistor; and a pair of output transistors configured to amplify an output voltage of the pair of the input transistors, one of the pair of output transistors feeding back the output voltage to the second resistor, one other of the pair of output transistors outputting the output voltage to a third resistor connected to the one end of the first detecting resistor; and an offset canceller configured to hold an output of the first detector as an offset voltage when the low-side switch is off and compensate the output of the first detector by the offset voltage when the low-side switch is on, the low-side controller being configured to compare a compensated output of the first detector with a reference voltage and turn off the low-side switch.