TOP414GN Power Integrations, TOP414GN Datasheet - Page 3

IC SW PWM DC-DC 48VDC 12W 8SMD

TOP414GN

Manufacturer Part Number
TOP414GN
Description
IC SW PWM DC-DC 48VDC 12W 8SMD
Manufacturer
Power Integrations
Series
TOPSwitch®r
Type
Step-Down (Buck), Step-Up (Boost), Flyback, Forward Converterr
Datasheet

Specifications of TOP414GN

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Frequency - Switching
120kHz
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
8-SMD Gull Wing
Output Voltage
5.8 V
Input / Supply Voltage (max)
265 VAC
Input / Supply Voltage (min)
85 VAC
Duty Cycle (max)
70 %
Switching Frequency
120 KHz
Supply Current
1.4 mA
Operating Temperature Range
- 40 C to + 150 C
Mounting Style
SMD/SMT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Output
-
Voltage - Output
-
Voltage - Input
-
Power - Output
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
TOPSwitch Family Functional Description
TOPSwitch is a self biased and protected linear control current-
to-duty cycle converter with an open drain output. High
efficiency is achieved through the use of CMOS and integration
of the maximum number of functions possible. CMOS
significantly reduces bias currents as compared to bipolar or
discrete solutions. Integration eliminates external power resistors
used for current sensing and/or supplying initial start-up bias
current.
During normal operation, the internal output MOSFET duty
cycle linearly decreases with increasing CONTROL pin current
as shown in Figure 4. To implement all the required control,
bias, and protection functions, the DRAIN and CONTROL pins
each perform several functions as described below. Refer to
Figure 2 for a block diagram and Figure 6 for timing and voltage
waveforms of the TOPSwitch integrated circuit.
Control Voltage Supply
CONTROL pin voltage V
is the supply or bias voltage for the
C
controller and driver circuitry. An external bypass capacitor
closely connected between the CONTROL and SOURCE pins
is required to supply the gate drive current. The total amount of
capacitance connected to this pin (C
) also sets the auto-restart
T
timing as well as control loop compensation. V
either of two modes of operation. Hysteretic regulation is used
for initial start-up and overload operation. Shunt regulation is
used to separate the duty cycle error signal from the control
circuit supply current. During start-up, V
from a high-voltage switched current source connected internally
between the DRAIN and CONTROL pins. The current source
provides sufficient current to supply the control circuitry as
well as charge the total external capacitance (C
Auto-restart
D MAX
D MIN
Figure 4. Relationship of Duty Cycle to CONTROL Pin Current.
5.7 V
4.7 V
V C
0
V IN
DRAIN
0
is regulated in
C
5.7 V
current is supplied
C
4.7 V
V C
0
).
T
V IN
DRAIN
0
Figure 5. Start-up Waveforms for (a) Normal Operation and (b)
Auto-restart.
TOP412/414
I B
Slope = PWM Gain
-16%/mA
I CD1
2.5
6.5
I C (mA)
I C
Charging C T
Off
Switching
(a)
I CD2
Discharging C T
I C
I CD1
Charging C T
Discharging C T
8 Cycles
95%
5%
Off
Off
Switching
Switching
(b)
C
is the total external capacitance
T
connected to the CONTROL pin
4/99
45
PI-1691-112895
Off
PI-1124A-060694
A
3

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