THV3543 Datasheet, PDF (14/19 Pages) THine Electronics, Inc. – 2 channel Buck/Boost 2 channel Charge Pump Controller

THV3543_Rev.1.00_E
Under Voltage Protection (UVP)
UVP is protective function which shuts down the power supply, when under voltage condition of DC/DC, VGH and
VGL caused by short circuit continues for more than a definite period of time. The internal comparator monitors the
output voltage. If the output voltage drops below a definite value, timer latch circuit starts operating (See Figure 4).
When abnormal output continues for more than 12.2msec, the device stops switching operation and goes into latch
state. If UVLO operates before the device goes into the latch state, the timer will be reset.
As to VGH and VGL, UVP detection does not operate for 3msec immediately after start-up sequence. Please set the
start-up time of charge pumps within 15msec to prevent start-up failure.
Output Voltage
Detection
AMP
or
COMP
-
+
VREF
UVP COMP
-
+
Vth
Timer
Latch
Figure 4. Under Voltage Detection Circuit
Over Voltage Protection (OVP)
OVP is protective function which shuts down the power supply when output voltage on CH-1 and CH-2 exceed a
defined voltage. CH-1 stops switching operation, when the voltage on INV1 pin exceeds 1.5V. CH-2 stops switching
operation, when the voltage on VO2_IN pin exceeds 4.13V (See Figure 5) .
As to CH-2, if abnormal output is detected, timer latch circuit operates. When abnormal output continues for
2.44msec, the device stops switching operation and goes into latch state.
Output Voltage
Dtection
AMP
-
+
SS
VREF
PWM COMP
OUT
OVP COMP
-
+
Vth
Figure 5. Over Voltage Detection Circuit
Over Current Protection (OCP)
CH-1 and CH-2 have built-in over current protection circuit. When load current exceeds a definite current, OCP stops
switching operation of the device. OCP operates at more than 4.0A on CH-1, 3.5A on CH-2.
If over current is detected continuously, low duty switching pulse is generated and that causes output voltage drop.
When output voltage drops below a definite voltage for more than 12.2msec, UVP operates and the device goes into
latch state.
Copyright© 2011 THine Electronics, Inc.
14/19
THine Electronics, Inc.