CS2844 Datasheet, PDF (5/12 Pages) Cherry Semiconductor Corporation – Current Mode PWM Control Circuit with 50% Max Duty Cycle

CS2844, CS3844, CS2845, CS3845
ELECTRICAL CHARACTERISTICS (continued) (–25° ≤ T_A ≤ 85° for CS2844/2845, 0° ≤ T_A ≤ 70° for CS3844/CS3845.
V_CC = 15 V*; R_T = 10 kΩ, C_T = 3.3 nF for sawtooth mode; unless otherwise stated.)
CS2844
CS3844
CS2845/CS3845
Characteristic
Test Conditions
Undervoltage Lockout Section
Start Threshold
–
Min Typ Max Min Typ Max Min Typ Max _Unit
15
16
17 14.5 16 17.5 7.8 8.4 9.0
V
Min. Operating Voltage After Turn On
9.0 10
11 8.5 10 11.5 7.0 7.6 8.2
V
*Adjust V_CC above the start threshold before setting at 15 V.
PACKAGE PIN DESCRIPTION
Package Pin Number
DIP–8 & SO–8 SO–14
Symbol
1
1
3
2
3
4
3
5
5
4
7
6
5
9
11
–
8
10
6
10
12
–
11
13
7
12
14
8
14
15
–
2, 4, 6, 13 1, 2, 7, 8,
9, 16
Symbol
COMP
V_FB
Sense
OSC
GND
Pwr GND
V_OUT
V_CC Pwr
V_CC
V_REF
NC
Description
Error amp output, used to compensate error amplifier.
Error amp inverting input.
Noninverting input to Current Sense Comparator.
Oscillator timing network with capacitor to ground, resistor to V_REF.
Ground.
Output driver ground.
Output drive pin.
Output driver positive supply.
Positive power supply.
Output of 5.0 V internal reference.
No connection.
4.7 kΩ
1.0 kΩ
ERROR AMP
ADJUST
4.7 kΩ
2N2222
100 kΩ
5.0 kΩ
Sense
ADJUST
R_T
COMP
V_FB
Sense
OSC
V_REF
V_CC
0.1 µF
V_OUT
GND
A
1.0 kΩ
1.0 W
0.1 µF
V_REF
V_CC
V_OUT
C_T
Figure 2. Test Circuit Open Loop Laboratory Test Fixture
GND
http://onsemi.com
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