Patent ID: 7741894
Filing Date: 2010-06-22
Classification: H03K

Abstract:
1. An output circuit, comprising: an output transistor supplying a load current to a load; a control signal input circuit supplying a switching signal to turn on/off the output transistor in response to an external switching signal applied to the control signal input circuit; a load current detecting block detecting a current level of a current flowing through the output transistor; a first off-rate adjustment circuit coupled between a gate terminal and a source terminal of the output transistor and including a depression-type MOS transistor, the depression-type MOS transistor having a gate terminal coupled with a first output terminal of the load current detecting block; and a second off-rate adjustment circuit coupled between the gate terminal and the source terminal of the output transistor and including an enhancement-type MOS transistor, the enhancement-type MOS transistor having a gate terminal coupled with a second output terminal of the load current detecting block, wherein the load current detecting block outputs a first activation signal, which is dependent on the switching signal to turn off the output transistor, at the first output terminal to turn on the depression-type MOS transistor when the load current detecting block detects a first current level flows through the output transistor, and the load current detecting block outputs a second activation signal, which is independent from the external switching signal, to the second output terminal to turn on the enhancement-type MOS transistor when the load current detecting block detects a second current level larger than the first current level flows through the output transistor.