MIC5013 Micrel Semiconductor, MIC5013 Datasheet - Page 12

• Manufacturer Part Number: MIC5013
• Description: Protected High- or Low-Side MOSFET Driver
• Manufacturer: Micrel Semiconductor

MIC5013
Applications Information
The top-side driver is based on the bootstrapped circuit of
Figure 6, and cannot be switched on indefinitely. The
bootstrap capacitor (1 F) relies on being pulled to ground
by the bottom-side output to recharge. This limits the
maximum duty cycle to slightly less than 100%.
Two of these circuits can be connected together to form an
H-bridge. If the H-bridge is used for locked antiphase
control, no special considerations are necessary. In the
case of sign/magnitude control, the “sign” leg of the H-
bridge should be held low (PWM input held low) while the
other leg is driven by the magnitude signal.
If current feedback is required for torque control, it is
available in chopped form at the bottom-side driver's 22 m
current-sensing resistor.
Time-Delay Relay (Figure 12). The MIC5013 forms the
basis of a simple time-delay relay. As shown, the delay
commences when power is applied, but the 100 k /1N4148
could be independently driven from an external source such
MIC5013
INPUT
PWM
22k
2N3904
1N4148
22k
(Continued)
220pF
20k
10k
1nF
Figure 11. Half-Bridge
10k
1
2
3
4
Thresh
Sense
Source
Input
Motor Driver
MIC5013
1
2
3
4
Thresh
Source
Input
Sense
MIC5013
Fault
Gate
Gnd
12
V+
as a switch or another high-side driver to give a delay
relative to some other event in the system.
Hysteresis has been added to guarantee clean switching at
turn-on. Note that an over-current condition latches the
relay in a safe, OFF condition. Operation is restored by
either cycling power or by momentarily shorting pin 1 to
ground.
Motor Driver with Stall Shutdown (Figure 13). Tachom-
eter feedback can be used to shut down a motor driver
circuit when a stall condition occurs. The control switch is a
3-way type; the “START” position is momentary and forces
the driver ON. When released, the switch returns to the
“RUN” position, and the tachometer’s output is used to hold
the MIC5013 input ON. If the motor slows down, the tach
output is reduced, and the MIC5013 switches OFF. Resis-
tor “R” sets the shutdown threshold. If the output current
exceeds 30A, the MIC5013 shuts down and remains in that
condition until the momentary “RESET” button is pushed.
Control is then returned to the START/RUN/STOP switch.
Fault
Gate
8
7
6
5
Gnd
V+
100nF
8
7
6
5
15k
15V
1N5817
100
+
1µF
10µF
+
15V
1N4001 (2)
IRF541
IRF541
22m
CPSL-3
(Dale)
22m
CPSL-3
(Dale)
M
12V,
10A Stalled
July 2000
Micrel