MIC5022_05 Datasheet, PDF (9/10 Pages) Micrel Semiconductor – Half-Bridge MOSFET Driver

MIC5022
10µF
TTL Input
(PWM signal)
MIC5022
1 _VDD
V_BOOST ¹⁴
2 _{Input Gate H} 13
3 _{Fault Sense H–} 12
4 _{CTH Sense H+} 11
5 _{Enable Gate L} 10
6 _CTL
7 _Gnd
Sense L– ⁹
Sense L+ ⁸
+12V to +20V
0.01µF
M
0.01µF
R_S1
R_S2
Micrel, Inc.
MIC5022
14 _VBOOST
V_DD ¹
13 _{Gate H Input} 2
12 _{Sense H– Fault} 3
11 _{Sense H+ CTH} 4
10 _{Gate L Enable} 5
9 _{Sense L– CTL} 6
8 _{Sense L+ Gnd} 7
10µF
TTL Input
(PWM signal)
Figure 2. Full-Bridge Motor Control Application
Synchronous Rectifier Converter
The MIC5022 can be part of a synchronous rectifier in SMPS
(switch mode power supply) applications.
This circuit uses the MIC38C43 SMPS controller IC to switch
a pass transistor (Q1) and a “synchronous rectifier” transistor
(Q2) using the MIC5022.
The MIC38C43 controller switches the transistors at 50kHz.
Output regulation is maintained using PWM. When the pass
transistor is on, the synchronous rectifier is off and current is
forced through the inductor to the output capacitor and load.
When the pass transistor is switched off, the synchronous
rectifier is switched on allowing current to continue to flow
as the inductor returns stored energy.
The synchronous rectifier MOSFET has a lower voltage drop
than the forward voltage drop across a Schottky diode. This
increases converter efficiency which extends battery life in
portable equipment.
+12V
10k
13k
47k ^0.15µF
3.3k
2200pF
300k
MIC38C43
4.7nF 1
Comp
8
V_REF
4.3k ₂
FB
7
V_DD
3
I_S
6
V_OUT
4
R_T/C_T
5
Gnd
10k
0.1µF
470µF
25V
MIC5022
1
V+ Gate H
5
Enable V_PP
2
Input Gate L
8
S L+
S H+
9
S L–
S H–
7
Gnd
Fault
0.1µF
13
14
10
11
12
3
SMP06N06-14
Q1
5mΩ
70µH
Q2
V_OUT
5V, 8A
1000µF
Low ESR
Figure 3. 50kHz Synchronous Rectifier Converter
July 2005
9
MIC5022