The TPS4021x is a peak current-mode control low-side controller with a built in 400-mA gate driver designed to drive n- channel MOSFETs at a fixed frequency. The frequency is adjustable from 35 kHz to 1000 kHz. Small size combined with complete functionality makes the part both versatile and easy to use.
The controller uses a low-value current-sensing resistor in series with the power MOSFET's source connection to detect switching current. When the voltage drop across this resistor exceeds 150 mV, the part enters an hiccup fault mode with a time period set by the external soft-start capacitor.
The TPS40210 uses voltage feedback to an error amplifier that is biased by a precision 700-mV reference. The TPS40211 has a lower 260-mV reference for higher efficiency in LED drive applications. Internal slope compensation eliminates the characteristic sub-harmonic instability of peak current mode control with duty cycles of 50% or greater.
The TPS4021x also incorporates a soft-start feature where the output follows a slowly rising soft-start voltage, preventing output-voltage overshoot. The DIS/EN disables the TPS40210 putting it in a low quiescent current shutdown mode.