93334

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

3 of 5

www.unisonic.com.tw

QW-R121-006,A

BLOCK DIAGRAM AND TYPICAL APPLICATION

Figure 1

+

-

+

-

* Optional parts for extended transient protection

** A350V zener clamp is required when using the standard BU941

Dwell

Reference

Buffer

Input

Comparator

Power

Output

&OVP

Ignition

Coil

Primary

8.0mH

Power Ground

21

3

C

4

5

with

Hysteresis

CFilter

0.2

300

100

5.0k

**BU941

Current

Limit

Sense

100

35-350

0.075

0.1

0.01

470

R

12k

20k

20k

UTC 93334

Reluctor

Pickup

1.35H

Component Values

Pickup

Series resistance = 800Ω±10% @ 25℃, inductance= 1.35H @ 1.0kHz @ 15Vrms

Coil

Leakage L=0.6mH, primary R=0.43Ω±5% @ 25℃, primary L=7.5mH ~ 8.5mH @ 5.0A

Load resistor for pickup=10Ω±20%

Input buffer resistors provide additional transient protection to the already clamped

inputs=20k±20%

For reduction of high frequency noise and spark transients induced in pick-up and leads;

optional and non-critical

CFilter

Stores reference, circuit designed for 0.1µF±20%

below Darlington turn-on during load dump = 100Ω±20%, 5.0W

Starting with 35Ω assures less than 5.5A, increasing as required to set 5.5A