tea1752t NXP Semiconductors, tea1752t Datasheet - Page 12

• Manufacturer Part Number: tea1752t
• Description: Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1752T_LT
Product data sheet
7.2.10 Mains undervoltage lockout/brownout protection (VINSENSE pin)
7.2.8 Dual boost PFC
7.2.9 Overcurrent protection (PFCSENSE pin)
The PFC output voltage depends on the mains input voltage. The mains input voltage is
measured via the VINSENSE pin. Current is sourced from the VOSENSE pin if the
voltage on the VINSENSE pin drops below 2.2 V (typical). To ensure a stable switch-over,
a 200 mV transition region is inserted around the 2.2 V, see
For low VINSENSE input voltages, the output current is 15 μA (typical). This output
current, in combination with the resistors on the VOSENSE pin, sets a lower PFC output
voltage level at low mains voltages. At high mains input voltages the current is switched to
zero. The PFC output voltage will then be at its maximum. As this current is zero in this
situation, it does not effect the accuracy of the PFC output voltage.
For proper switch-off behavior, the VOSENSE current is switched to its maximum value,
(15 μA (typical)), as soon as the voltage on pin VOSENSE drops below 2.1 V (typical).
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 continuously monitored. When the voltage on this pin drops below the
V
Fig 6. PFC start/stop via PFCTIMER pin
Fig 7.
stop(VINSENSE)
Voltage to current transfer function for dual boost PFC
level, PFC switching is stopped.
All information provided in this document is subject to legal disclaimers.
low power
I
I(VOSENSE)
Rev. 02 — 24 June 2010
SENSE1
−15 μA
, on the source of the external MOSFET. The voltage is
10 μA
14
TEA1752T; TEA1752LT
1.27 V
PFCTIMER
3.6 V
2.2 V
R
S
V
Q
GreenChip III SMPS control IC
VINSENSE
Figure
014aaa097
low power delay
(PFC on)
014aaa740
7.
© NXP B.V. 2010. All rights reserved.
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