DATA SHEET
Preliminary specification
File under Integrated Circuits, IC11
1998 Aug 19
INTEGRATED CIRCUITS
TEA1501
Greeny; GreenChip
TM
1998 Aug 19
2
Philips Semiconductors
Preliminary specification
Greeny; GreenChip
TM
TEA1501
FEATURES
Direct off-line operation (90 to 276 V AC)
Low external component count
Integrated high voltage startup current source for a fast
startup within 0.25 s
Integrated power switch: 650 V, 40
, 0.25 A
Programmable primary peak current
Data transfer from isolated secondary side to
non-isolated primary side via the transformer
On/Off function replaces expensive mains switch by a
functional switch.
Green features
Low current consumption in Off mode, typical 40
A
Efficient burst mode operation, for 0.1 to 3 W output
power.
Protection features
Cycle-by-cycle current control with programmable
primary peak current
Over-voltage protection
Under-voltage lockout
Over-temperature protection.
GENERAL DESCRIPTION
The TEA1501 (Greeny) is the low power member of the
GreenChip
TM
family and is especially designed for standby
switched mode power supply applications. Greeny
incorporates all the necessary functions for an efficient
and low cost power supply for 90 to 276 V AC universal
input. Greeny is a monolithic integrated circuit and is
available in a DIP8 package. The design is made in the
BCD_PowerLogic750 process and includes the high
voltage switching device. Using only 7 functional pins,
Greeny contains extensive control functions to form a
flexible and a reliable power supply with a minimum of
external components. Greeny operates in a flyback
topology (see Fig.1) with a fixed switching frequency,
constant primary peak current control and regulates the
output voltage in burst mode.
Applications include low power supplies and standby
power supplies as used in television, monitor, lighting
electronics and domestic appliances with an output power
from 0.1 to 3 W.
BASIC FLYBACK CONFIGURATION
Fig.1 Basic flyback configuration.
handbook, full pagewidth
MGM823
TEA1501
on/off
np
na
ns
(1)
Vout
Vin
Vzener
load
Src
OOD
Bt
Ref
RSrc
CBt
RRef
Drn
n.c.
Gnd
Vaux
(1) The secondary earthing point is isolated from the primary earthing points.
1998 Aug 19
3
Philips Semiconductors
Preliminary specification
Greeny; GreenChip
TM
TEA1501
QUICK REFERENCE
ORDERING INFORMATION
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
V
on/off
on/off level Greeny
0.4
0.7
0.9
V
V
data(off)
data off level
20
A < I
OOD
< 100
A
0.9
1.3
1.6
V
V
data(on)
data on level
20
A < I
OOD
< 100
A
3.5
4.0
4.5
V
I
start
startup current, Vaux pin
V
Vaux
= 8 V, V
OOD
> 0.9 V
-
2.4
-
1.8
-
1.2
mA
I
Drn(off)
drain current in Off mode
V
OOD
< 0.4 V
-
40
100
A
V
BD
breakdown voltage
I
Drn(off)
+ 100
A
650
-
-
V
R
dson
on resistance
T
j
= 25
C, I
Drn
= 80 mA
25
40
55
V
detect
detection level
0.47
0.50
0.53
V
TYPE NUMBER
PACKAGE
NAME
DESCRIPTION
VERSION
TEA1501
DIP8
plastic dual in-line package; 8 leads (300 mil)
SOT97-1
1998 Aug 19
4
Philips Semiconductors
Preliminary specification
Greeny; GreenChip
TM
TEA1501
BLOCK DIAGRAM
Fig.2 Block diagram.
handbook, full pagewidth
MGM820
Vaux MANAGEMENT
REFERENCE BLOCK
TEMPERATURE
PROTECTION
SWITCH
OSCILLATOR
startup current source
SUPPLY CURRENT
TRACKING
MODULATOR
on/off level
data off
data on
BURST OSCILLATOR
LOGIC
TEA1501
COUNTER
power
switch
GATE DRIVER
LEADING EDGE
BLANKING
5
6
3
2
4
8
1
Vdetect
Drn
OOD
Gnd
Vaux
Ref
Bt
Src
PINNING
SYMBOL
PIN
DESCRIPTION
Src
1
source of the power switch and input
for primary current sensing
OOD
2
on/off input and data transfer output
Bt
3
input for burst capacitor
Ref
4
input for reference resistor
Vaux
5
supply input of the IC and input for
voltage regulation
Gnd
6
ground
n.c.
7
not connected to comply with safety
requirements
Drn
8
drain of the power switch and input
for startup current
Fig.3 DIL8 Package.
handbook, halfpage
1
2
3
4
8
7
6
5
MGM821
TEA1501
Drn
n.c.
OOD
Gnd
Vaux
Ref
Bt
Src
1998 Aug 19
5
Philips Semiconductors
Preliminary specification
Greeny; GreenChip
TM
TEA1501
FUNCTIONAL DESCRIPTION
The TEA1501 contains a high voltage power switch, a high
voltage startup circuit and low voltage control circuitry on
the same IC. Together with a transformer and a few
external components a low power, isolated, flyback
converter can be built. The Greeny system operates in a
burst mode. During each burst period the output voltage is
regulated to a desired voltage level.
System operation
O
N
/O
FF
The Greeny system can be switched on and off by means
of a low cost, low voltage switch. In the Off mode the
startup current source and power switch are disabled. In
the On mode, Greeny delivers the startup current for the
supply capacitor and after the supply voltage reaches the
startup level Greeny activates the power switch.
S
TARTUP
The startup is realized with a high voltage startup current
source instead of a dissipative bleeder resistor which is
commonly used by low voltage control ICs. When Greeny
is switched on, the startup current source is enabled and
starts charging the Vaux capacitor. The startup current
level is high and accurate (typical 1.8 mA) which results in
a well-defined and short startup time, within 0.25 s. After
the supply voltage reaches the startup level the current
source is switched off and the Vaux capacitor supplies the
chip. Reducing the power dissipation in the current source
to zero after startup is one of the green features of Greeny.
O
PERATION
After startup the flyback converter starts delivering energy
to the secondary and auxiliary winding. The Greeny
system works with fixed switching frequency and fixed
peak current.
As all the windings of the flyback transformer have the
same flux variation, the secondary voltage and the
auxiliary voltage are related via the turns-ratio (n
s
/n
a
).
Therefore, the isolated secondary voltage is controlled by
the non-isolated auxiliary voltage.
The burst mode operates by switching at high frequency
until the Vaux voltage reaches its regulation level of 20 V.
Greeny stops switching until the time period set by the
burst oscillator has expired. At the start of the next burst
period Greeny starts switching at high frequency and
repeats the cycle again.
To guarantee a stable operation in a burst mode controlled
system a Vaux slope compensation circuit is integrated in
Greeny. The Greeny system delivers a constant voltage to
the secondary load until a burst duty cycle of 40%.
D
ATA TRANSFER
The TEA1501 has a data transfer function which makes
communication from the isolated secondary side to the
non-isolated primary side of the transformer possible,
without using an opto-coupler. This communication
function is activated by increasing the secondary load.
With this data transfer function a main power supply can
be switched on and off by the Greeny system.
The power delivered to the secondary and auxiliary
winding is proportional to the number of primary current
pulses per burst period, provided that the converter
operates in discontinuous conduction mode. During each
burst period the number of primary current pulses is
counted. A threshold (N
data
) of 56 pulses is integrated. The
clamp level on the OOD pin is set to data-on level from
data-off level in case the N
data
threshold is passed. This
data-on clamp level can be sensed by the on/off input of a
main supply control IC of the GreenChip
TM
family. The
data-on clamp level is maintained until a burst appears
with a number of pulses below the N
data
threshold.
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