Patent ID: 9024558
Filing Date: 2015-05-05
Classification: H02P,H03K

Abstract:
1. A bridge output circuit comprising: an output terminal to be connected to a load; a high side transistor interposed between an upper power line and the output terminal; a low side transistor interposed between the output terminal and a lower power line, the low side transistor being an N-channel MOSFET; a high side driver configured to control a gate voltage of the high side transistor; a low side driver configured to control a gate voltage of the low side transistor; and a controller configured to control the high side driver and the low side driver, wherein the low side driver includes: a first current source configured to switch between a turning-on state and a turning-off state and supply a first predetermined constant current to a gate of the low side transistor in the turning-on state; a second current source configured to switch between the turning-on state and the turning-off state and draw a second predetermined constant current out of the gate of the low side transistor in the turning-on state; and a first assist circuit configured to switch between the turning-on state and the turning-off state and draw a first auxiliary current out of the gate of the low side transistor in the turning-on state, the first assist circuit being provided separately from the second current source, and wherein the controller is further configured to control the turning-on state and the turning-off state of the first current source, the second current source and the first assist circuit such that, when transitioning an output voltage of the output terminal from a low level voltage to a high level voltage in a state where a load current flows from the output terminal in a direction in which the load current is absorbed into the bridge output circuit, the bridge output circuit goes to a first state where the first current source is turned off and the first assist circuit is turned on, and transitions to a second state where the first current source is turned off, the second current source is turned on and the first assist circuit is turned off when the output voltage exceeds a predetermined lower threshold voltage.