High Voltage Power Supply based PWM IC TL494

TP1 industrial design, a coil is designed for 220. 2 and 3 are designed for 12V, 2-I (upper diagram) is designed to return 10.8 A. TR 2 consists of a high-voltage winding (used in the factory with 800 coils), power coils containing 10.12 (chosen experimentally) and a feedback consisting of 28 turns, current transformer TP3 consists of a current of one coil winding and winding connection of 24 turns (to increase the sensitivity necessary to increase the number of turns)

The principle of operation of the high power supply

The High voltage power supply is based on a common PWM IC TL494. A feature included is the use of two comparators, an error is allowed to make adjustments to current and voltage. Another feature is the use of chips in single-ended converter, the scheme with a single push-pull signal channel, it is possible to avoid the opening of the power transistor for a time more than half a stroke and did not avoid the complete closure, allowing him to more clearly signal to operate without a key, which is much reduced the temperature of the transistor (it was established a practical method). Adjusting the current is carried by a signal from the sensor current control of voltage on a signal with an additional transformer. PWM chip has a separate power supply is not connected with the power circuit. To increase the output voltage applied to common multiplier UN8, 5/25-1, 2. Combining the power circuit minus-minus high-voltage circuit enabled us to avoid damage to circuits and PWM power switch in contact with high voltage to the control unit housing and ground body of the instrument allows you to completely exclude this possibility and to protect the user.

High Voltage Power Supply Specifications:
Voltage: 220 volts AC 50 Hz.
Output voltage adjustable from 1 to 15 kV *.
Adjust the output current, short circuit protection .**

Rules of operation:
voltage regulator & ratings at the lowest position, the current regulator in the secondary, connect kilovoltmeter, run the installation by connecting cord and turn on, set the correct voltage, adjust the current limit.

Safety:
Do not touch the high voltage circuits are not sure of the absence of power and discharge circuit.

When connecting / reconnecting the power circuits to turn the unit off, pull the power cord, power circuit discharge resistor of 3 milliohms or more within a few minutes, then discharge the remaining short-circuited (never discharged immediately short-circuited in order to avoid damage to the power circuits).

source :www.cxem.net