| 摘要 |
A current sensing circuit is provided to reduce complexity of a design and to occupy a small area if the current sensing circuit is produced as a real chip. A current sensing circuit for sensing current flowing in an MOS(Metal-Oxide Semiconductor) transistor(503) by calculating a voltage drop value of the MOS transistor is composed of an amplifier(510), a PMOS(P-channel Metal Oxide Semiconductor) transistor, and first and second resistors(501,502). One end of the first resistor is connected with a source of the MOS transistor and the other end is coupled with a negative input stage(512) of the amplifier and a source of the PMOS transistor. The second resistor is connected between a ground and a drain of the PMOS transistor. A positive input stage(511) of the amplifier is connected to a drain of the MOS transistor. The output of the amplifier is coupled to a gate of the PMOS transistor. The current sensing circuit calculates a voltage drop value by using sensing voltage(Vsense) that is a drain voltage of the PMOS transistor, and first and second resistor values. |
