tea1753lt NXP Semiconductors, tea1753lt Datasheet - Page 13

• Manufacturer Part Number: tea1753lt
• Description: Tea1753lt Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1753LT
Objective data sheet
7.2.12 PFC open-loop protection (VOSENSE pin)
7.2.13 Driver (pin PFCDRIVER)
7.2.11 Overvoltage protection (VOSENSE pin)
7.3.1 Multimode operation
7.3 Flyback controller
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
of 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
500 mA and a current sink capability of 1.2 A. This permits fast turn-on and turn-off of the
power MOSFET for efficient operation.
The TEA1753LT includes a controller for a flyback converter. The flyback converter
operates in quasi-resonant or discontinuous conduction mode with valley switching. The
auxiliary winding of the flyback transformer provides demagnetization detection and
powers the IC after start-up.
The TEA1753LT flyback controller can operate in several modes; see
Fig 8.
Multimode operation flyback
frequency
switching
flyback
125 kHz
86 kHz
48 kHz
All information provided in this document is subject to legal disclaimers.
I
adjust
pmin
Rev. 01 — 4 March 2011
frequency
reduction
th(ol)(VOSENSE)
PFC off
PFC on
level. This protects the circuit from open-loop
discontinuous
with valley
switching
ovp(VOSENSE)
GreenChip III SMPS control IC
output power
ovp(VOSENSE)
TEA1753LT
quasi-resonant
014aaa745
level again.
Figure
© NXP B.V. 2011. All rights reserved.
level, switching
8.
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