MIC5011_05 Datasheet, PDF (9/12 Pages) Micrel Semiconductor – Minimum Parts High- or Low-Side MOSFET Driver

MIC5011
Applications Information (Continued)
Micrel, Inc.
15V
1N4003 (2)
100kΩ
10mA
Control Input
4N35
33pF
33kΩ
MIC5011 ^1N4746
1 _V+
C1 ⁸
2 _{Input Com} 7
MPSA05 _{3 Source C2 6 1nF}
4 _{Gnd Gate} 5
+ 100µF
90V
IRFP250
100kΩ
1kΩ
1/4 HP, 90V
5BPB56HAA100 M
(GE)
100nF
200V
15Vp-p, 20kHz
Squarewave
1N4003
Figure 7. High-Voltage
Bootstrapped Driver
diode limits the supply to 18V. When the MIC5011 is off,
power is supplied by a diode connected to a 15V supply. The
circuit of Figure 5 is put to good use as a barrier between
low voltage control circuitry and the 90V motor supply.
Half-Bridge Motor Driver (Figure 8). Closed loop control
of motor speed requires a half-bridge driver. This topology
presents an extra challenge since the two output devices
should not cross conduct (shoot-through) when switching.
Cross conduction increases output device power dissipa-
tion. Speed is also important, since PWM control requires
the outputs to switch in the 2 to 20kHz range.
The circuit of Figure 8 utilizes fast configurations for both
the top- and bottom-side drivers. Delay networks at each
input provide a 2 to 3µs dead time effectively eliminating
cross conduction. Two of these circuits can be connected
together to form an H-bridge for locked antiphase or sign/
magnitude control.
15V
1N5817
1N4148
22kΩ 220pF
100nF
MIC5011
1 _V+
C1 ⁸
2 _{Input Com} 7
3 _{Source C2} 6
4 _{Gnd Gate} 5
1N4001 (2)
+
1µF
IRF541
PWM
INPUT
22kΩ
2N3904
15V
10kΩ
1nF
+
10µF
MIC5011
1 _V+
C1 ⁸
2 _{Input Com} 7
3 _{Source C2} 6
4 _{Gnd Gate} 5
M
12V,
10A Stalled
IRF541
July 2005
Figure 8. Half-Bridge
Motor Driver
9
MIC5011