FAN6791 Datasheet, PDF (9/19 Pages) Fairchild Semiconductor – Highly Integrated, Dual-PWM Combination Controller

Electrical Characteristics
VDD=18V; RI=24kΩ;TA =25°C, unless noted.
Symbol
Parameter
Conditions
Min.
Typ.
Max. Units
Forward PWM Stage
FBPWM-Feedback Input
AV
FB to Current Comparator
Attenuation
1/3.2
1/2.7
1/2.2
V/V
ZFB
VHGH
VOPEN-PWM
Input Impedance
Output High Voltage
PWM Open-Loop Protection
Voltage
FB Pin Open
4
5
5.0
5.2
7
kΩ
V
4.2
4.5
4.8
V
tOPEN-PWM-
HICCUP
tOPEN-PWM
Interval of PWM Open-Loop
Protection Reset
PWM Open-Loop Protection
Delay Time
RI=24kΩ
RI=24kΩ
500
600
700
ms
80
95
120
ms
VOZ-OPWM VFBPWM for Zero Duty Cycle
IPWM-Current Sense
1.2
1.3
1.4
V
tPD
VLIMIT1
Propagation Delay to Output –
VLIMIT Loop
Peak Current Limit Threshold
Voltage 1
VDD=15V, OPWM
Drops to 9V
VRMS=1V
60
120
ns
0.75
0.80
0.85
V
VLIMIT2
Peak Current Limit Threshold
Voltage 2
VRMS=1.5V
VLIMIT1-0.1
V
tBNK
ΔVSLOPE
Leading-Edge Blanking Time
Slope Compensation
ΔVs=ΔVSLOPE x (ton/t)
ΔVs: Compensation Voltage
Added to Current Sense
270
350
450
ns
0.40
0.45
0.55
V
OPWM-GATE Driver
VOPWM-CLAMP
Output Voltage Maximum
(Clamp)
VDD=22V
16
18
V
VOL
Output Voltage Low
VOH
Output Voltage High
tR
Rising Time
VDD=15V; IO=100mA
VDD=13V; IO=100mA
8
VDD=15V; CL=5nF;
O/P=2V to 9V
30
1.5
V
V
60
120
ns
tF
Falling Time
VDD=15V; CL=5nF;
O/P=9V to 2V
30
50
110
ns
FAN6791 Maximum Duty Cycle
DCYMAX-OPWM
RI=24kΩ
FAN6793 Maximum Duty Cycle
47
48
49
%
60
65
70
Soft Start
ISS
Constant Current Output for
Soft-Start
RI=24kΩ
17
20
23
µA
RD
Discharge Resistance
470
564
Ω
Notes:
1. When activated, the output is disabled and the latch is turned off.
2. This is the threshold temperature for enabling the output again and resetting the latch after over-temperature
protection has been activated.
© 2008 Fairchild Semiconductor Corporation
FAN6791 / FAN6793 • Rev. 1.0.2
9
www.fairchildsemi.com