TEA1791T Philips Semiconductors, TEA1791T Datasheet - Page 4

• Manufacturer Part Number: TEA1791T
• Description: GreenChip Synchronous Rectifier Controller
• Manufacturer: Philips Semiconductors

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NXP Semiconductors
TEA1791T_1
Product data sheet
7.4 Supply management
7.5 Driver
If the secondary stroke of the flyback converter is shorter than 2 s (typ), the driver output
is disabled. This will guarantee stable operation for very low duty cycles. When the
secondary stroke increases above 2.2 s (typ), the driver output is again enabled.
All (internal) reference voltages are derived from a temperature compensated, on-chip
band gap circuit.
The driver circuit to the gate of the external power MOSFET has a source capability of
typically 250 mA and a sink capability of typically 2.7 A. This permits fast turn-on and
turn-off of the power MOSFET for efficient operation. The output voltage of the driver is
limited to 10 V (typical). This high output voltage will drive all MOSFET brands to the
minimum on-state resistance.
During start-up conditions (V
voltage is actively pulled low.
Fig 3.
V
Secondary
SRSENSE
V
Primary
DRIVER
current
current
Synchronous rectification signals
Rev. 01 — 3 February 2009
CC
< V
startup
) and undervoltage lockout the driver output
GreenChip synchronous rectifier controller
TEA1791T
© NXP B.V. 2009. All rights reserved.
014aaa057
0 V
0 A
0 A
0 V
12 mV
55 mV
310 mV
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