tea1751lt NXP Semiconductors, tea1751lt Datasheet - Page 11

• Manufacturer Part Number: tea1751lt
• Description: Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1751T_LT_1
Product data sheet
7.2.10 Overvoltage protection (VOSENSE pin)
7.2.11 PFC open loop protection (VOSENSE pin)
7.2.12 Driver (pin PFCDRIVER)
7.2.8 Overcurrent protection (PFCSENSE pin)
7.2.9 Mains undervoltage lockout / brownout protection (VINSENSE 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 voltage on pin VINSENSE is clamped to a minimum value,
V
restored after a 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.
The driver circuit to the gate of the power MOSFET has a current sourcing capability of
typically 500 mA and a current sink capability of typically 1.2 A. This permits fast turn-on
and turn-off of the power MOSFET for efficient operation.
Fig 6.
stop(VINSENSE)
start(VINSENSE)
Voltage to current transfer function for dual boost PFC
level, switching of the PFC is stopped.
V
pu(VINSENSE)
I
I(VOSENSE)
Rev. 01 — 10 July 2008
SENSE1
15 A
th(ol)(VOSENSE)
, for a fast restart as soon as the mains input voltage is
, on the source of the external MOSFET. The voltage is
TEA1751T; TEA1751LT
level. This protects the circuit from open loop
2.2 V
ovp(VOSENSE)
V
GreenChip III SMPS control IC
VINSENSE
ovp(VOSENSE)
014aaa097
level again.
© NXP B.V. 2008. All rights reserved.
level, switching of
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