FAN302UL Datasheet, PDF (15/19 Pages) Fairchild Semiconductor – PWM Controller for Low Standby Power Battery-Charger Applications

Figure 41. V_S OVP Protection
Leading-Edge Blanking (LEB)
Each time the power MOSFET is switched on, a turn-on
spike occurs at the sense resistor. To avoid premature
termination of the switching pulse, a 150ns leading-edge
blanking time is built in. Conventional RC filtering can
therefore be omitted. During this blanking period, the
current-limit comparator is disabled and it cannot switch
off the gate driver.
Noise Immunity
Noise from the current sense or the control signal can
cause significant pulse-width jitter. While slope
compensation helps alleviate these problems, further
precautions should still be taken. Good placement and
layout practices should be followed. Avoid long PCB
traces and component leads and, locate bypass filter
components near the PWM IC.
© 2011 Fairchild Semiconductor Corporation
FAN302UL • Rev. 1.0.3
15
www.fairchildsemi.com