TEA1654T NXP Semiconductors, TEA1654T Datasheet - Page 5

• 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
PINNING
2003 May 12
handbook, halfpage
VCOadj
I
STDBY
DRIVER
HVS
HVS
DRAIN
V
n.c.
GND
V
LOCK
CTRL
DEM
SYMBOL PIN
sense
CC
CC(5V)
GreenChip II SMPS control IC
DRIVER
VCOadj
STDBY
10
11
12
13
14
DRAIN
I sense
1
2
3
4
5
6
7
8
9
HVS
HVS
Fig.3 Pin configuration.
VCO adjustment input
programmable current sense input
standby indication or control output
gate driver output
high voltage safety spacer, not
connected
high voltage safety spacer, not
connected
drain of external MOS switch, input for
start-up current and valley sensing
supply voltage
not connected
ground
5 V output
lock input
control input
input from auxiliary winding for
demagnetization timing, OVP and OPP
1
2
3
4
5
6
7
TEA1654T
MDB216
DESCRIPTION
14
13
12
11
10
9
8
DEM
CTRL
LOCK
V CC(5V)
GND
n.c.
V CC
5
FUNCTIONAL DESCRIPTION
The TEA1654 is the controller of a compact flyback
converter, with the IC situated at the primary side.
An auxiliary winding of the transformer provides
demagnetization detection and powers the IC after
start-up.
The TEA1654 operates in multi modes (see Fig.4).
The next converter stroke is started only after
demagnetization of the transformer current (zero current
switching), while the drain voltage has reached the lowest
voltage to prevent switching losses (green function). The
primary resonant circuit of primary inductance and drain
capacitor ensures this quasi-resonant operation. The
design can be optimized in such a way that zero voltage
switching can be reached over almost the complete
universal mains range.
To prevent very high frequency operation at lower loads,
the quasi-resonant operation changes smoothly in fixed
frequency PWM control.
At very low power (standby) levels, the frequency is
controlled down, via the VCO, to a minimum frequency of
approximately 24 kHz.
Start-up, mains enabling operation level and
undervoltage lock-out (see Figs 11 and 12)
Initially, the IC is self supplying from the rectified mains
voltage via pin DRAIN. Supply capacitor C
by the internal start-up current source to a level of
approximately 4 V (or higher, this is dependent on the
drain voltage/M-level). Once the drain voltage exceeds the
M-level (mains-dependent operation-enabling level), the
start-up current source will continue charging
capacitor C
The IC will activate the power converter as soon as the
voltage on pin V
supply is taken over by the auxiliary winding as soon as the
output voltage reaches its intended level and the IC supply
from the mains voltage is subsequently stopped for high
efficiency operation (green function).
The moment the voltage on pin V
undervoltage lock-out level V
and enters a safe restart from the rectified mains voltage.
Inhibiting the auxiliary supply by external means causes
the converter to operate in a stable safe restart mode.
Supply management
All (internal) reference voltages are derived from a
temperature compensated, on-chip band gap circuit.
VCC
(switch S1 will be opened); see Fig.2.
CC
passes the level V
UVLO
CC
, the IC stops switching
drops below the
Product specification
CC(start)
TEA1654
VCC
. The IC
is charged