Toshiba 29VH27D, Service Manual

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14.19.3.Pin Connections
14.19.4.Pin Function description
Pin Name Description
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 start–up 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 stand–by mode.
3 Control Input A feedback current from the secondary side of the SMPS via the opto–coupler 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 Stand–by 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 V
CC
This 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 Vi This pin can be directly connected to a 500V voltage source for start–up function of the
IC. During the Start–up phase a 9 mA current source is internally delivered to the V
CC
pin 6 allowing a rapid charge of the V CC capacitor. As soon as the IC starts –up, this
current source is disabled.
14.20.TCET1102G
14.20.1.Description
The TCET110/ TCET2100/ TCET4100 consists of a phototransistor optically coupled to a gallium
arsenide infrared-emitting diode in a 4-lead up to 16-lead plastic dual inline package. The elements are
mounted on one lead frame using a
coplanar techniqu
e, providing a fixed distance between input and
output for highest safety requirements.
14.20.2.Applications
Circuits for safe protective separation against electrical shock according to safety class II (reinforced
isolation):
For appl. class I – IV at mains voltage =300 V
For appl. class I – III at mains voltage =600 V
According to VDE 0884, table 2, suitable for:
Switch-mode power supplies, line receiver, computer
peripheral interface, microprocessor system interface.
14.20.3.Features
VDE 0884 related features:
Rated impulse voltage (transient overvoltage) V
IOTM
= 8 kV peak
Isolation test voltage (partial discharge test voltage) V
pd
= 1.6 kV
Rated isolation voltage (RMS includes DC) V
IOWM
= 600 V
RMS
(848 V peak)
Rated recurring peak voltage (repetitive) V
IORM
= 600 V
RMS