Current sensing circuit of a switching mode power supply

摘要

When a signal having a large shifted level is needed in a level shift circuit, a false operation is generated by the increase of noise level. And, when the signal level is very low, the circuit does not operate and generates distortion. The present circuit improves such problems. To do this, a capacitor or diode for coupling a signal generated from a signal source and level shifter for shifting the DC-coupled signal by a predetermined shift level is utilized. Accordingly, a variation of a small signal is transmitted without distortion to exactly and precisely control a device and noise level is reduced in a source signal transmission process, thereby preventing false operation of the device.