TEA1750 NXP Semiconductors, TEA1750 Datasheet - Page 11

• Manufacturer Part Number: TEA1750
• Description: GreenChip III SMPS control IC
• Manufacturer: NXP Semiconductors

www.datasheet4u.com
NXP Semiconductors
TEA1750_2
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 / brownout 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
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. As the VOSENSE pin draws a small input current,
switching is also inhibited when the pin is left open.
Fig 6.
stop(VINSENSE)
start(VINSENSE)
start(fb)
Burst mode control
level and the flyback converter is also disabled.
peak current
level, switching of the PFC is stopped. If the low mains situation continues,
V
envelop of
VOSENSE
V
pu(VINSENSE)
Rev. 02 — 15 December 2008
SENSE1
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
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
level again.
TEA1750
© NXP B.V. 2008. All rights reserved.
level, switching of
11 of 29