HA16107P Datasheet, PDF (10/40 Pages) Hitachi Semiconductor – PWM Switching Regulator for High-performance Voltage Mode Control

HA16107P/FP, HA16108P/FP
Undervoltage Lockout and PWM Output
The undervoltage lockout function turns off the PWM pulse output when the controller’s supply voltage goes below a
designated value. These ICs have two undervoltage lockout circuits. The UVL1 circuit senses the supply voltage V_IN.
The UVL2 circuit senses the Vref voltage. A feature of these ICs is that PWM output is turned on only when both
voltages are above designated values. Otherwise, the IC operates in standby mode.
The two built-in undervoltage lockout circuits make it possible to configure an extremely safe power supply system.
PWM output will shut down under a variety of abnormal conditions, such as if Vref is shorted to ground while V_IN is
applied.
• UVL1 (V_IN and Vref)
*¹
I_IN
9.5 V ^{16.2 V}
0
10 V
Vref
*²
0
10 V
• UVL2 (Vref and PWM output)
20 V
30 V
6.45 V
34 V
V_IN
Notes: 1. Breakdown voltage of
the internal Zener
diode (V_z = 34 V typ).
2. Hysteresis characteristic.
20 V
30 V
V_IN
Vref
6.45 V
5V
4V
0
10 V
20 V
30 V
V_IN
OUT
Operating region
0
10 V
20 V
30 V
PWM output shut-down region
• UVL1 and UVL2
V_IN (UVL1)
Vref (UVL2)
L
H
H
L
L
H
PWM OUT
L
L
OUT
Standby mode

Note: Double circles indicate standby mode.
V_IN
L
H
L
Rev.4.00 Jun 15, 2005 page 10 of 39