TEA1623PH Philips Semiconductors, TEA1623PH Datasheet - Page 5

• Manufacturer Part Number: TEA1623PH
• Description: STARplug
• Manufacturer: Philips Semiconductors

Philips Semiconductors
8. Functional description
9397 750 12579
Product data sheet
7.2 Pin description
8.1 Start-up and undervoltage lock-out
8.2 Oscillator
Table 3:
The TEA1623P; TEA1623PH is the heart of a compact flyback converter, with the IC
placed at the primary side. The auxiliary winding of the transformer can be used for
indirect feedback to control the isolated output. This additional winding also powers the IC.
A more accurate control of the output voltage and/or current can be implemented with an
additional secondary sensing circuit and optocoupler feedback.
The TEA1623P; TEA1623PH uses voltage mode control. The frequency is determined by
the maximum transformer demagnetizing time and the time of the oscillator. In the first
case, the converter operates in the Self Oscillating Power Supply (SOPS) mode. In the
latter case, it operates at a constant frequency, which can be adjusted with external
components R
Furthermore, a primary stroke is started only in a valley of the secondary ringing. This
valley switching principle minimizes capacitive switch-on losses.
Initially, the IC is self supplying from the rectified mains voltage. The IC starts switching as
soon as the voltage on pin V
auxiliary winding of the transformer as soon as V
the line is stopped for high efficiency operation.
As soon as the voltage on pin V
and restarts from the rectified mains voltage.
The frequency of the oscillator is set by the external resistor and capacitor on pin RC. The
external capacitor is charged rapidly to the V
stroke, it discharges to the V
relative sensitivity of the duty factor to the regulation voltage at low duty factor is almost
Symbol
V
GND
RC
REG
SGND
AUX
SOURCE 6
n.c.
DRAIN
CC
Pin
TEA1623P
1
2
3
4
-
5
7
8
Pin description
RC
and C
Rev. 01 — 17 March 2004
RC
TEA1623PH
3
4
5
6
8
11
12
1, 2, 7, 9, 10,
13, 15, 16
14
. This mode is called Pulse Width Modulation (PWM).
CC
RC(min)
passes the V
CC
drops below the V
level. Because the discharge is exponential, the
Description
supply voltage
ground
frequency setting
regulation input
signal ground; must preferably be connected to pin GND
input for voltage from auxiliary winding for timing
(demagnetization)
source of internal MOS switch
not connected
drain of internal MOS switch; input for start-up current
and valley sensing
TEA1623P; TEA1623PH
RC(max)
CC(start)
CC
level and, starting from a new primary
level. The supply is taken over by the
is high enough and the supply from
CC(stop)
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
level, the IC stops switching
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STARplug
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