FAN8902 Fairchild Semiconductor, FAN8902 Datasheet - Page 8

• Manufacturer Part Number: FAN8902
• Description: Motor / Motion / Ignition Controllers & Drivers Fan Motor Controller DC
• Manufacturer: Fairchild Semiconductor
• Type: Fan Motor Controllerr

Specifications of FAN8902

• Operating Current: 8mA
• Operating Temperature Classification: Industrial
• Package Type: PDIP
• Operating Supply Voltage (typ): 12V
• Product: Fan / Motor Controllers / Drivers
• Operating Supply Voltage: 32 V
• Supply Current: 8 mA
• Mounting Style: Through Hole
• Package / Case: DIP-14
• Operating Temperature: - 40 C to + 90 C
• Lead Free Status / RoHS Status: Compliant

6. Slope Compensation
An unconditional instability of the inner current loop exists for any fixed frequency current-mode converter operating above
50% duty cycle. Therefore, to guarantee current loop stability, the slope of the compensation ramp must be greater than
one-half of the down slope of the current waveform. The ramp voltage for slope compensation is as follow,
7. Motor Stall Current Limitation
V RAMP
V
CMD
=
R14
---------- -
R11
V OSC
CMD
1
R12
FAN8902
4R
R
Slop Compensation
V
CMD
C2
R11
I*
TR2
Buffer-OP-amp
+
V
+
+
CS
PWM
COMP
Logic
VBAT
R14
5
V
LA
14
12
10
+
C1
Vref
C4
C2
R10
1
5
6
Q1
R2
R3
_
R5
+
D1
FAN8902
V
GS
OSC
R
S
M
Q2
V
IM
RS
Comparator
To PWM
FAN8902(KA3902)
8