HR1000A – RESONANT HALF-BRIDGE CONTROLLER
FLOW CHART
START
VCC capacitor is charged
through pull-up resistor
N
VCC>10.5V
Y
Soft Start
Normal Operation
switching frequency
is modulated by IFset
Burst
Latched
Shutdown
OCP
OCP
OTP
Brown-out
UVLO
Mode
Monitor Thermal
Monitor CS
Monitor TIMER
Monitor BO
Monitor VCC
Monitor Burst
Monitor LATCH
N
N
N
N
N
N
N
BO>4.7V or
BO<1.25V
Burst<1.25V
Y
>10ºC
CS>0.8V
Y
TIMER>2V
Y
VCC<8V
Y
LATCH>1.85V
Y
Y
Y
1. Stop the
switching pulse
2. PFC pin pulled
low
1. Stop the
switching pulse
2. Soft start
capacitor fully
discharged
1. Stop the
switching pulse
2. Soft start
capacitor fully
discharged
1. Stop the
switching pulse
2. Soft start
capacitor fully
discharged
1. Latch off the
switching pulse
2. Soft start
capacitor fully
discharged
1. Increase the
switching
frequency
2. Soft start
capacitor
begin to
1. Switching
frequency is
pushed to
maximum value
2. Soft start
capacitor fully
discharge
3. PFC pin pulled
low
3. PFC pin pulled
low
discharge
3. TIMER
3. TIMER
N
capacitor is
charged by an
internal 150uA
current source
Burst>1.3V
Y
capacitor is
charged by an
internal 150uA
current source
4 PFC pin pulled
low
N
N
N
N
<120ºC
VCC>12V
Y
1.25V<BO<6V
Y
VCC<6.4V
Y
1. Resume the
switching pulse
2. PFC pin pulled
high
Y
N
CS>1.5V
Y
N
TIMER>3.5V
Y
1. Latch off the
switching pulse
2. Soft start
capacitor fully
discharged
1. Stop the
switching pulse
2. Soft start
capacitor fully
discharged
3. PFC pin pulled
low
3. TIMER
capacitor
discharged by
external resistor
4. PFC pin pulled
low
N
VCC<6.4V
Y
N
TIMER<0.3V
Y
HR1000A Rev. 1.01
8/30/2012
www.MonolithicPower.com
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© 2012 MPS. All Rights Reserved.
21
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