H3842S Datasheet, PDF (6/10 Pages) Hi-Sincerity Mocroelectronics – HIGH PERFORMANCE CURRENT MODE CONTROLERS

HI-SINCERITY
MICROELECTRONICS CORP.
Spec. No. : HS200203
Issued Date : 2001.04.01
Revised Date : 2002.12.03
Page No. : 6/10
Application Information
Open Loop Test Circuit
Vref
4.7KΩ
RT
HPN2222A
100KΩ
Error Amp.
Adjust _1KΩ
I SENSE
Adjust _5KΩ
4.7KΩ
VREF
COMP
1
VFB
2
I SENSE
3
RT/CT
4
8
H3842
7 ^Vcc
Output
6
Ground
5
0.1uF
0.1uF
A
1W
1KΩ
Vcc
Output
Ground
CT
High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and
bypass capacitors should be connected close to pin5 in a single point ground. The transistor and 5KΩ
potentiometerare used to samplethe oscillator waveform and apply an adjustable ramp to pin3.
Oscillator and Output Waveforms
Vcc
8
RT
4
7
5V REG
PWM
1
3
2
Clock
Oscillator
Id
6
Output
CT
5
GND
CT
Output
CT
Output
Large RT / Small CT
Small RT / Large CT
Error Amp Configuration
Under Voltage Lockout
2.5V
+
Zi
VFB 2
-
COMP 1
Zf
7 ^{ON/OFF Command}
Icc
1mA
Vi
To Rest Of IC
<17mA
H3842
Von 16V
Voff 10V _<0.5mA
Vcc
Voff Von
H3842S
HSMC Product Specification