UC3844B, 45B UC2844B, 45B
Figure 23. Current Waveform Spike Suppression
VCC
Vin
7(12)
5.0V Ref
+
–
+
–
T
S
Q
R
Comp/Latch
7(11)
Q1
6(10)
5(8)
3(5)
R
C
RS
The addition of the RC filter will eliminate
instability caused by the leading edge spike
on the current waveform.
Figure 24. MOSFET Parasitic Oscillations
VCC
Vin
7(12)
5.0V Ref
+
–
+
–
7(11)
Rg
Q1
T
S
Q
R
Comp/Latch
6(10)
5(8)
3(5)
RS
Series gate resistor Rg will damp any high frequency
parasitic oscillations caused by the MOSFET input
capacitance and any series wiring inductance in the
gate–source circuit.
Figure 25. Bipolar Transistor Drive
IB
+
Vin
0
Base Charge
–
Removal
C1
Q1
6(10)
5(8)
3(5)
RS
The totem pole output can furnish negative base current
for enhanced transistor turn–off, with the addition of
capacitor C1.
MOTOROLA ANALOG IC DEVICE DATA
11