A novel current detection method suitable for switching regulators

A new method of current detection for switching regulators is proposed. Using the relationship between the load current in discontinuous mode (DCM) and the gate drive signal N_DRV of the synchronous tube, the output load current of the switching regulator is detected by detecting the gate signal. This method reduces the circuit complexity brought about by directly detecting the average current of the inductor, and saves the cost of chip design. Using 0.5μm CMOS process, Hspice simulation verification, it only consumes 5μA quiescent current. Keywords: switching regulator; discontinuous mode (DCM); current detection 1. Introduction With the development of electronic products towards miniaturization and portability, monolithic integrated high-efficiency, low-power supply voltage DC-DC converters are widely used application. Current detection circuits are used in many power management ICs. In the current mode PWM control DC-DC converter, the current detection module is an important part of the current loop, used to detect the current flowing through the power tube and the inductor, and through the current detection result and the output of the voltage loop Make a comparison to achieve the effect of pulse width modulation. In voltage mode pulse width modulation DC-DC converter (PWM DC-DC Converter), low dropout linear regulator (LDO), charge pump (Charge Pump) and other circuits, it can also be used as open circuit, short circuit, over current And other energy-saving and protective purposes. There are three traditional current detection methods: use the R[sub]DS[/sub] of the power tube for detection; use the detection field-effect transistor for detection; combine the field-effect transistor and the detection resistor. Aiming at the switching regulator, which is different from the traditional current detection method, this paper proposes a novel switching regulator load current detection method. 2. Traditional current detection method 2.1 Use the R[sub]DS[/sub] of the power tube for detection (RDS SENSING) We know that when the power tube (POWER MOSFET) is turned on, it works in the variable resistance area and can wait The effect is a resistance, and the equivalent resistance is: A novel current detection method suitable for switching regulators