IC CTLR SYNC RECTIFIER 8SOIC

TEA1791AT/N1,118

Manufacturer Part NumberTEA1791AT/N1,118
DescriptionIC CTLR SYNC RECTIFIER 8SOIC
ManufacturerNXP Semiconductors
SeriesGreenChip™
TEA1791AT/N1,118 datasheet
 

Specifications of TEA1791AT/N1,118

Package / Case*Mounting Type*
Voltage - Supply8.5 V ~ 38 VOperating Temperature-20°C ~ 150°C
ModeDiscontinuous Conduction (DCM)Input / Supply Voltage (max)38 V
Input / Supply Voltage (min)8.5 VSupply Current0.95 mA
Operating Temperature Range- 40 C to + 150 CMounting StyleSMD/SMT
Maximum Operating Temperature+ 150 CMinimum Operating Temperature- 40 C
Output Current3 ALead Free Status / RoHS StatusLead free / RoHS Compliant
Frequency - Switching-Current - Startup-
Other names935290157118  
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NXP Semiconductors
7. Functional description
7.1 Introduction
The TEA1791AT is the controller for synchronous rectification to be used in discontinuous
conduction mode and quasi-resonant flyback converters.
7.2 Start-up and UnderVoltage LockOut (UVLO)
The IC leaves the undervoltage lockout state and activates the synchronous rectifier
circuitry as soon as the voltage on the V
voltage drops below 8.0 V (typical), the undervoltage lockout state is reentered and the
SR driver output is actively kept low.
7.3 Synchronous rectification
After a negative voltage (−310 mV typical) is sensed on the SRSENSE pin, the driver
output voltage is driven 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
driver output is pulled to ground.
When the SR MOSFET is switched on, the input signal on the SRSENSE pin is blanked
for 0.93 μs (typical). This eliminates false switch-off due to high frequency at the start of
the secondary stroke.
Because the driver output voltage is reduced as soon as the voltage on the SRSENSE pin
is −55 mV, the external power switch can be switched off quickly when the current through
the switch reaches zero. With this zero current switch-off, no separate Standby mode is
needed to maintain high efficiency during the no-load operation. The zero current is
detected by sensing a −12 mV level on the SRSENSE pin (see
TEA1791AT
Product data sheet
GreenChip synchronous rectifier controller
pin is above 8.5 V (typical). As soon as the
CC
All information provided in this document is subject to legal disclaimers.
Rev. 01 — 7 June 2010
TEA1791AT
Figure
3).
© NXP B.V. 2010. All rights reserved.
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