TEA1506T Ver la hoja de datos (PDF) - Philips Electronics
Número de pieza
componentes Descripción
Fabricante
TEA1506T Datasheet PDF : 22 Pages
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Philips Semiconductors
GreenChip™II SMPS control IC
Product specification
TEA1506P; TEA1506AP;
TEA1506T; TEA1506AT
Control pin protection
If pin CTRL is open-circuit or not connected, a fault
condition is assumed and the converter will stop switching.
Operation will recommence as soon as the fault condition handbook, halfpage
is removed.
ISS
Soft start-up
To prevent transformer rattle during hiccup, the
transformer peak current is slowly increased by the soft
start function. This can be achieved by inserting a resistor
and a capacitor between pin Isense and the sense resistor
(see Fig.11). An internal current source charges the
capacitor to V = ISS × RSS, with a maximum of
approximately 0.5 V.
The start level and the time constant of the increasing
primary current level can be adjusted externally by
changing the values of RSS and CSS.
Iprimary(max) = V-----o--c---p----–--R--(--sI--S-e--nS---s--×e-----R----S---S----)
τ = RSS × CSS
The charging current ISS will flow as long as the voltage on
pin Isense is below approximately 0.5 V. If the voltage on
pin Isense exceeds 0.5 V, the soft start current source will
start limiting the current ISS. At the VCC(start) level, the ISS
current source is completely switched off.
Since the soft start current ISS is supplied from pin DRAIN,
the RSS value will not affect the VCC current during start-up.
0.5 V
start-up
5 Isense RSS
Vocp
CSS
Rsense
MGU237
Fig.11 Soft start.
Driver
The driver circuit to the gate of the power MOSFET has a
current sourcing capability of 135 mA typical and a current
sink capability of 560 mA typical. This permits fast turn-on
and turn-off of the power MOSFET for efficient operation.
A low driver source current has been chosen to limit the
∆V/∆t at switch-on. This reduces Electro Magnetic
Interference (EMI) and also limits the current spikes
across Rsense.
2003 Sep 09
11
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