Current detection circuit and current detection method
AssigneeNEC Electronics Corporation
InventorKenji Amada
Life of this patent
Estimating the term…
Abstract
A multi-source MOS transistor includes a sense MOS transistor and a load MOS transistor, and is connected to a load. A current detection portion has a negative input offset voltage characteristic, and detects a first sense current in a state where it is connected to the power supply and the sense MOS transistor and a second sense current in a state where it is connected to the sense MOS transistor and the load MOS transistor. A calculation control portion calculates a load current based on the first sense current and the second sense current such that the effect of the input offset voltage in the current detection portion is cancelled.
Claims7
A current detection circuit comprising:
- a multi-source MOS transistor having a sense MOS transistor and a load MOS transistor, the multi-source MOS transistor being connected to a power supply and a load;
- a current detection portion having a negative input offset voltage characteristic to detect sense current flowing through the sense MOS transistor, one input of the current detection portion being connected to the power supply or the load MOS transistor, and the other input of the current detection portion being connected to the sense MOS transistor;
- and
- a calculation control portion to calculate load current flowing through the load based on a first sense current and a second sense current such that the effect of the input offset voltage is cancelled, the first sense current being the sense current when the current detection portion is connected to the power supply, and the second sense current being the sense current when the current detection portion is connected to the load MOS transistor.
A method of detecting load current flowing a load using:
- a multi-source MOS transistor having a sense MOS transistor and a load MOS transistor, the multi-source MOS transistor being connected to a power supply and the load;
- and
- a current detection portion having a negative input offset voltage characteristic;
- the method comprising:
- connecting the current detection portion to the sense MOS transistor and the power supply, and detecting a first sense current;
- connecting the current detection portion to the sense MOS transistor and the load MOS transistor, and detecting a second sense current;
- and
- calculating the load current based on the first sense current and the second sense current such that the effect of the input offset voltage is cancelled.
Dependencies are inferred from the claim text.