TEA1761T 查看數據表（PDF） - NXP Semiconductors.
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TEA1761T Datasheet PDF : 13 Pages
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NXP Semiconductors
6. Pinning information
6.1 Pinning
TEA1761T
GreenChip synchronous rectifier controller
SRSENSE 1
GND 2
n.c. 3
DRIVER 4
8 VCC
7 ISENSE
TEA1761T
6 VSENSE
5 OPTO
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Fig 2. Pin configuration for TEA1761T
6.2 Pin description
Table 2. Pin description
Symbol
Pin
SRSENSE
1
GND
2
n.c.
3
DRIVER
4
OPTO
5
VSENSE
6
ISENSE
7
VCC
8
Description
synchronous timing input
ground
not connected
driver output for SR MOSFET
opto coupler driver output
sense input for voltage control
sense input for current control
supply voltage
7. Functional description
The TEA1761T is the controller for synchronous rectification to be used in discontinuous
conduction mode and quasi resonant flyback converters. Besides controlling the
SR MOSFET, the TEA1761T contains the voltage reference and amplifiers to regulate and
control the output voltage and current of the power supply.
7.1 Start-up and undervoltage lock out
The IC leaves the under-voltage lock-out state and activates the synchronous rectifier
circuitry and also the voltage/current sense circuitry as soon as the voltage on the VCC pin
is above 8.6 V (typical). As soon as the voltage drops below 8.1 V (typical), the
under-voltage lock-out state is re-entered and the SR driver output is actively kept low and
also the opto driver output is disabled.
7.2 Synchronous rectification
After a negative voltage (−310 mV typical) is sensed on the SRSENSE pin, the driver
output voltage is made high and the external MOSFET is switched on. As soon as the
SRSENSE voltage rises to −55 mV, the driver output voltage is regulated to maintain the
−55 mV on the SRSENSE pin. As soon as the SRSENSE voltage is above −12 mV, the
TEA1761T_2
Product data sheet
Rev. 02 — 25 April 2007
© NXP B.V. 2007. All rights reserved.
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