TEA1654T NXP Semiconductors, TEA1654T Datasheet - Page 8

• Manufacturer Part Number: TEA1654T
• Manufacturer: NXP Semiconductors

Specifications of TEA1654T

• Operating Temperature (max): 145C
• Operating Temperature (min): -20C
• Pin Count: 14
• Mounting: Surface Mount
• Package Type: SO
• Screening Level: Commercial
• Lead Free Status / Rohs Status: Compliant

Philips Semiconductors
Operation only recommences when the V
below a level of approximately 4.5 V (practically when the
V
The output voltage (V
can be set by the demagnetization resistor R
where N
number of auxiliary turns of the transformer.
Current I
The value of the demagnetization resistor (R
adjusted to the turns ratio of the transformer, thus making
an accurate OVP possible.
2003 May 12
V
handbook, full pagewidth
mains
OVP
GreenChip II SMPS control IC
A: Start of new cycle at lowest drain voltage.
B: Start of new cycle in a classical PWM system at high drain voltage.
=
has been disconnected for a short period).
s
OVP(DEM)
----------- -
N
is the number of secondary turns and N
N
aux
s
I
OVP DEM
is internally trimmed.
OVP
secondary
) at which the OVP function trips,
oscillator
stroke
valley
R
drain
DEM
+
primary
V
stroke
clamp DEM pos
CC
Fig.8 Signals for valley switching.
voltage drops
DEM
DEM
secondary
) can be
stroke
:
aux
is the
8
Valley switching (see Fig.8)
A new cycle starts when the power switch is switched on.
After the ‘on-time’ (which is determined by the ‘sense’
voltage and the internal control voltage), the switch is
opened and the secondary stroke starts.
After the secondary stroke, the drain voltage shows an
oscillation with a frequency of approximately
where L
and C
------------------------------------------
2
d
secondary
is the capacitance on the drain node.
1
p
ringing
L
is the primary self inductance of the transformer
p
C
d
B
MGU235
A
Product specification
TEA1654