mp6001dn MPS, mp6001dn Datasheet - Page 6

• Manufacturer Part Number: mp6001dn
• Description: Monolithic Flyback/forward Dc-dc Converter
• Manufacturer: MPS

High Voltage Startup
The MP6001 features a 100V startup circuit,
see Figure 1. When power is applied, the
capacitor at the VCC pin is charged through the
VIN pin. When the voltage at the VCC pin
crosses 6.0V without fault, the controller is
enabled. The VCC pin is then disconnected
from the VIN pin and V
via the operating current. When V
4.5V, the VCC pin is reconnected to the VIN pin
and V
VCC pin repeats this ramp cycle between 4.5V
and 6.0V. The VCC pin can be powered with a
voltage higher than 4.5V from an auxiliary
winding to reduce the power dissipated in the
internal startup circuit. The VCC pin is internally
clamped at 8V.
Under-Voltage and Over-Voltage Detection
The MP6001 includes a line monitor circuit.
Two external resistors form a voltage divider
from the input voltage to GND; its tap connects
to the LINE pin. The controller is operational
when the voltage at the UV/OV pin is between
1.2V and 3V. When the voltage at the UV/OV
pin goes out of this operating range, the
controller is disabled and goes into standby
mode. The LINE pin can also be used as a
remote enable. Grounding the UV/OV pin will
disable the controller.
Error Amplifier
The MP6001 includes an error amplifier with its
non-inverting input connected to internal 1.2V
reference voltage. The regulated voltage is fed
back
optocoupler to the FB pin. Figure 2 shows some
common error amplifier configurations.
MP6001 Rev. 0.91
9/21/2007
CC
through
will be recharged. The voltage at the
TM
a
resistor
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
CC
voltage is discharged
network
MP6001 – MONOLITHIC FLYBACK/FORWARD DC-DC CONVERTER
CC
© 2007 MPS. All Rights Reserved.
drops to
or
www.MonolithicPower.com
an
PRIMARY
WINDING
Figure 2—Error Amplifier Configurations
C2
(a) Using Primary winding to provide feedback
(b) Feedback is from Secondary (Common Collector)
(c) Feedback is from Secondary (Common Emitter)
D1
C2
R2
C1
6
6
R1
R2
VCC
VCC
3
3
1.2V
1.2V
FB
FB
6
VCC
3
1.2V
FB
+
R3
+
--
--
EA
EA
R3
C2
+
--
EA
C3
4
4
COMP
COMP
MP6001_F02
4
COMP
6