TOP247YN Power Integrations, TOP247YN Datasheet - Page 6

• Manufacturer Part Number: TOP247YN
• Description: IC OFFLINE SWIT UVLO HV TO220
• Manufacturer: Power Integrations
• Series: TOPSwitch®-GXr
• Type: Off Line Switcherr

Specifications of TOP247YN

• Output Isolation: Isolated
• Frequency Range: 66 ~ 132kHz
• Voltage - Output: 700V
• Power (watts): 165W
• Operating Temperature: -40°C ~ 150°C
• Package / Case: TO-220-7 (Formed Leads), 5 Leads
• Output Voltage: 12 V
• Input / Supply Voltage (max): 265 VAC
• Input / Supply Voltage (min): 85 VAC
• Duty Cycle (max): 83 %
• Switching Frequency: 132 KHz
• Supply Current: 2.2 mA
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• Supply Voltage: 265VAC
• No. Of Pins: 6
• No. Of Regulated Outputs: 1
• Filter Terminals: Through Hole
• Output Voltage Max: 700V
• Rohs Compliant: Yes
• On Resistance Rds(on): 1.95ohm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 596-1078-5

CONTROL (C) Pin Operation
The CONTROL pin is a low impedance node that is capable
of receiving a combined supply and feedback current. During
normal operation, a shunt regulator is used to separate the
feedback signal from the supply current. CONTROL pin voltage
V
MOSFET gate driver. An external bypass capacitor closely
connected between the CONTROL and SOURCE pins is required
to supply the instantaneous gate drive current. The total amount
of capacitance connected to this pin also sets the auto-restart
timing as well as control loop compensation.
When rectified DC high voltage is applied to the DRAIN
pin during start-up, the MOSFET is initially off, and the
CONTROL pin capacitor is charged through a switched high
voltage current source connected internally between the DRAIN
and CONTROL pins. When the CONTROL pin voltage V
reaches approximately 5.8 V, the control circuitry is activated
and the soft-start begins. The soft-start circuit gradually
increases the duty cycle of the MOSFET from zero to the
maximum value over approximately 10 ms. If no external
feedback/supply current is fed into the CONTROL pin by the
end of the soft-start, the high voltage current source is turned
off and the CONTROL pin will start discharging in response
to the supply current drawn by the control circuitry. If the
power supply is designed properly, and no fault condition
such as open loop or shorted output exists, the feedback loop
will close, providing external CONTROL pin current, before
the CONTROL pin voltage has had a chance to discharge to
the lower threshold voltage of approximately 4.8 V (internal
supply under-voltage lockout threshold). When the externally
fed current charges the CONTROL pin to the shunt regulator
Figure 8. Typical Waveforms for (1) Power Up (2) Normal Operation (3) Auto-Restart (4) Power Down.
C
6
is the supply voltage for the control circuitry including the
TOP242-250
V
V
V
Note: S0 through S7 are the output states of the auto-restart counter
LINE
C
V
DRAIN
0 V
0 V
0 V
0 V
O
11/05
OUT
V
UV
1
S7
S0
2
S1
S2
S6
S7
3
S0
S1
C
S2
voltage of 5.8 V, current in excess of the consumption of the
chip is shunted to SOURCE through resistor R
Figure 2. This current flowing through R
of the power MOSFET to provide closed loop regulation. The
shunt regulator has a finite low output impedance Z
the gain of the error amplifier when used in a primary feedback
configuration. The dynamic impedance Z
pin together with the external CONTROL pin capacitance sets
the dominant pole for the control loop.
When a fault condition such as an open loop or shorted output
prevents the flow of an external current into the CONTROL
pin, the capacitor on the CONTROL pin discharges towards
4.8 V. At 4.8 V, auto-restart is activated which turns the output
MOSFET off and puts the control circuitry in a low current
standby mode. The high-voltage current source turns on and
charges the external capacitance again. A hysteretic internal
supply under-voltage comparator keeps V
of typically 4.8 V to 5.8 V by turning the high-voltage current
source on and off as shown in Figure 8. The auto-restart
circuit has a divide-by-eight counter which prevents the output
MOSFET from turning on again until eight discharge/charge
cycles have elapsed. This is accomplished by enabling the
output MOSFET only when the divide-by-eight counter reaches
full count (S7). The counter effectively limits TOPSwitch-GX
power dissipation by reducing the auto-restart duty cycle
to typically 4%. Auto-restart mode continues until output
voltage regulation is again achieved through closure of the
feedback loop.
Oscillator and Switching Frequency
The internal oscillator linearly charges and discharges an
S6
S7
2
S0
S1
S2
4
S6
E
S7
controls the duty cycle
C
C
S7
of the CONTROL
within a window
E
4.8 V
as shown in
PI-2545-082299
5.8 V
C
that sets