tea1750t-n1 NXP Semiconductors, tea1750t-n1 Datasheet - Page 11

• Manufacturer Part Number: tea1750t-n1
• Description: Tea1750 Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1750_1
Product data sheet
7.2.10 PFC open loop protection (VOSENSE pin)
7.2.7 Overcurrent protection (PFCSENSE pin)
7.2.8 Mains undervoltage lock-out / brown-out protection (VINSENSE pin)
7.2.9 Overvoltage protection (VOSENSE pin)
The maximum peak current is limited cycle-by-cycle by sensing the voltage across an
external sense resistor (R
measured via the PFCSENSE pin.
To prevent the PFC from operating at very low mains input voltages, the voltage on the
VINSENSE pin is sensed continuously. As soon as the voltage on this pin drops below the
V
the PFC bus voltage eventually drops. The voltage on the VOSENSE pin then drops below
the V
The voltage on pin VINSENSE is clamped to a minimum value, (V
mains dropout.
To prevent output overvoltage during load steps and mains transients, an overvoltage
protection circuit is built in.
As soon as the voltage on the VOSENSE pin exceeds the V
the power factor correction circuit is inhibited. Switching of the PFC recommences as
soon as the VOSENSE pin voltage drops below the V
When the resistor between pin VOSENSE and ground is open, the overvoltage protection
is also triggered.
The power factor correction circuit does not start switching until the voltage on the
VOSENSE pin is above the V
and VOSENSE short situations. As the VOSENSE pin draws a small input current,
switching is also inhibited when the pin is left open.
Fig 6. Burst mode control
V
stop(VINSENSE)
pu(VINSENSE)
start(fb)
level and the flyback converter is also disabled.
peak current
level, switching of the PFC is stopped. If the low mains situation continues,
for a fast restart as soon as the mains input voltage is restored after a
V
envelop of
VOSENSE
Rev. 01 — 6 April 2007
SENSE1
th(ol)(VOSENSE)
) on the source of the external MOSFET. The voltage is
soft-start
level. This protects the circuit from open loop
ton control
ovp(VOSENSE)
GreenChip III SMPS control IC
ovp(VOSENSE)
soft-stop
V
V
burst(L)
burst(H)
014aaa019
start(VINSENSE)
level again.
TEA1750
© NXP B.V. 2007. All rights reserved.
level, switching of
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