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CHASSIS
12.15.4. Pin Function description
PoN NAME DESCRoPToON
1 Demag The Demag pin offers 3 different functions: Zero voltage crossing detection
(50mV), 24mA current detection and 120mA current detection. The 24mA level
is used to detect the secondary reconfiguration status and the 120mA level to
detect an Over Voltage status called Quick OVP.
2 ISENSE The Current Sense pin senses the voltage developed on the series resistor
inserted in the source of the power MOSFET. When I sense reaches 1V, the
Driver output (pin 5) is disabled. This is known as the Over Current Protection
function. A 200mA current source is flowing out of the pin 3 during the startup
phase and during the switching phase in case of the Pulsed Mode of
operation. A resistor can be inserted between the sense resistor and the pin 3;
thus a programmable peak current detection can be performed during the
SMPS standby mode.
3 Control A feedback current from the secondary side of the SMPS via the optocoupler
Input is injected into this pin. A resistor can be connected between this pin and GND
to allow the programming of the Burst duty cycle during the Standby mode.
4 Ground This pin is the ground of the primary side of the SMPS.
5 Driver The current and slew rate capability of this pin are suited to drive Power
MOSFETs.
6 VCCThis pin is the positive supply of the IC. The driver output gets disabled when
the voltage becomes higher than 15V and the operating range is between 6.6V
and 13V. An intermediate voltage level of 10V creates a disabling condition
called Latched Off phase.
7 This pin is to provide isolation between the Vi pin 8 and the VCC pin 6.
8 ViThis pin can be directly connected to a 500V voltage source for startup
function of the IC. During the Startup phase a 9 mA current source is
internally delivered to the VCC pin 6 allowing a rapid charge of the VCC
capacitor. As soon as the IC startsup, this current source is disabled.
12.16. TL431 (Q816)
12.16.1. Description
The TL431 is a 3-terminal adjustable shunt voltage regulator providing a highly accurate 1 % band gap reference.
TL431 acts as an open-loop error amplifier with a 2.5V temperature compensation reference. The TL431 thermal
stability, wide operating current (150mA) and temperature range (0 to 105 makes it suitable for all variety of application
that are looking for a low cost solution with high performance. The output voltage may be adjusted to any value between
VREF and 36 volts with two external resistors. The TL431 is operating in full industrial temperature range of 0°C to
105°C.
12.16.2. Features
? Trimmed Band gap to 1%
? Wide Operating Current1mA to 150mA
? Extended Temperature Range0 °C to 105°C
12.16.3. Pin Configurations
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ACEC
