Diodes AP2160 - Manual (Page 7)

Preliminary Datasheet
Ultra Low Output Voltage Linear N-FET Controller AP2160
Jan. 2012 Rev. 1. 0 BCD Semiconductor Manufacturing Limited
7
Function Description
1. Power-On-Reset
A Power-On-Reset (POR) circuit monitors input
voltages at VCC pin to prevent wrong logic controls.
The POR function initiates a soft-start process after
the supply voltages exceed input voltage UVLO
threshold during powering on. The POR function also
pulls low the POK pin regardless of the output
voltage when the VCC voltage falls below the input
voltage UVLO threshold minus input voltage UVLO
hysteresis.
2. Output Voltage Regulation
An error amplifier working with a temperature
compensated 0.5V reference and an output NMOS
regulates output to the preset voltage. The error
amplifier designed with high bandwidth and DC gain
provides very fast transient response and excellent
load regulation.
3. Under-Voltage Protection (UVP)
AP2160 monitors the voltage on FB pin after
soft-start process finishing. Therefore the UVP is
disabled during soft-start. When the voltage on FB
pin falls below the output voltage UVLO Threshold,
the UVP circuit shuts down the output immediately.
4. Thermal Shutdown
A thermal shutdown circuit limits the junction
temperature of AP2160. When the junction
temperature exceeds 150°C, a thermal sensor turns
off the output NMOS, allowing the device to cool
down. The regulator regulates the output again
through initiation of a new soft-start cycle after the
junction temperature drops by 40°C.