2000 Sep 08
8
Philips Semiconductors
Product specification
STARplug
TM
TEA152x family
Minimum and maximum duty factor
The minimum duty factor of the switched mode power
supply is 0%. The maximum duty factor is set to 75%
(typical value at 100 kHz oscillation frequency).
Overcurrent protection
The cycle-by-cycle peak drain current limit circuit uses the
external source resistor to measure the current. The circuit
is activated after the leading edge blanking time t
leb
. The
protection circuit limits the source voltage to V
SRC(max)
,
and thus limits the primary peak current.
Short circuit winding protection
The short circuit winding protection circuit is also activated
after the leading edge blanking time. If the source voltage
exceeds the short circuit winding protection voltage V
swp
,
the IC stops switching. Only a Power-on reset will restart
normal operation. The short circuit winding protection also
protects in case of a secondary diode short circuit.
Overtemperature protection
An accurate temperature protection is provided in the
device. When the junction temperature exceeds the
thermal shutdown temperature, the IC stops switching.
During thermal protection, the IC current is lowered to the
start-up current. The IC continues normal operation as
soon as the overtemperature situation has disappeared.
Overvoltage protection
Overvoltage protection can be achieved in the application
by pulling pin REG above its normal operation level. The
current primary stroke is terminated immediately, and no
new primary stroke is started until the voltage on pin REG
drops to its normal operation level. Pin REG has an
internal clamp. The current feed into this pin must be
limited.
Output characteristics of complete powerplug
O
UTPUT POWER
A wide range of output power levels can be handled by
choosing the R
DS(on)
and package of the TEA152x family.
Power levels up to 50 W can be realised.
A
CCURACY
The accuracy of the complete converter, functioning as a
voltage source with primary sensing, is approximately 8%
(mainly dependent on the transformer coupling). The
accuracy with secondary sensing is defined by the
accuracy of the external components. For safety
requirements in case of optocoupler feedback loss, the
primary sensing remains active when an overvoltage
circuit is connected.
E
FFICIENCY
An efficiency of 75% at maximum output power can be
achieved for a complete converter designed for universal
mains.
R
IPPLE
A minimum ripple is obtained in a system designed for a
maximum duty factor of 50% under normal operating
conditions, and a minimized dead time. The magnitude of
the ripple in the output voltage is determined by the
frequency and duty factor of the converter, the output
current level and the value and ESR of the output
capacitor.
Input characteristics of complete powerplug
I
NPUT VOLTAGE
TheinputvoltagerangecomprisestheuniversalAC mains
(80 to 276 V).