U2350B-FP

TELEFUNKEN Semiconductors

Rev. A1, 29-May-96

3 (9)

Pin Description

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

n.c.

NTC

95 11409

Progr.

Contr.

LED1

LED2

OUT

OUT–

GND

OUT+

Pin

Symbol

Function

1

LED1

LED output 1

2

LED2

LED output 2

3

n.c.

Not connected

4

NTC

Monitoring input

5

Progr.

Tristate programing

6

Resistor for oscillator

7

Capacitor for oscillator

8

Contr.

Control input

9

Voltage regulation input

10

Switching output, output S1

11

Current regulation input

12

GND

Ground

13

OUT–

– supply for output stage

14

OUT

Output

15

OUT+

+ supply for output stage

16

Supply voltage

Supply, Pin 16

The internal voltage limiter in the U2350B enables a

simple supply from the rectified line voltage. The supply

supply current is simultaneously used to operate the two

supply current therefore reaches Pin 16 either via LEDs

R

1max

+

V

whereas

V

Mmin

+ V

V

Smax

+ maximum supply voltage

+ I

Smax

) I

x

I

Smax

+ Max. current consumption of the IC

+ Current consumption of the external components

mode of operation. For further information regarding

mains power supply, refer to figures 6 and 7.

Voltage Monitoring

Whilst the operating voltage is being built up or reduced,

uncontrolled output pulses of insufficient amplitude are

suppressed by the internal monitoring circuit. The latch

Pin 2 and Pin 16 is switched off and the control input

W

resistor. In connection with a switching hysteresis of

approximately 2 V, this mode of operation guarantees

fail-safe start-up each time the operating voltage is

switched on, in the same way as after short mains

interruptions.

Connecting the control input Pin 8 with a capacitor can

therefore make a soft start with rapid recovery possible.

Pulse Width Control with Mains Voltage

Compensation, Pins 8, 9, 10

Average value of the voltage over the load is controlled

to an infinitely selectable value by the comparator

Comp. 1 with hysteresis. The rectified mains voltage is

the inverting input of Comp. 1, is more positive than the

an impedance converter. During the charge time, which

is dependent of the mains voltage, the pulse output is at

high potential and the switching output Pin 10 is open. If

Comp. 1 switches over the output stage logic via an AND

gate.