MICREL MIC5022BWM

MIC5022
Micrel
MIC5022
Half-Bridge MOSFET Driver
General Description
Features
The MIC5022 half-bridge MOSFET driver is designed to
operate at frequencies up to 100kHz (5kHz PWM for 2% to
100% duty cycle) and is an ideal choice for high speed
applications such as motor control and SMPS (switch mode
power supplies).
A rising or falling edge on the input results in a current source
pulse or sink pulse on the gate outputs. This output current
pulse can turn on a 2000pF MOSFET in approximately 1µs.
The MIC5022 then supplies a limited current (< 2mA), if
necessary, to maintain the output states.
Two overcurrent comparators with nominal trip voltages of
50mV make the MIC5022 ideal for use with current sensing
MOSFETs. External low value resistors may be used instead
of sensing MOSFETs for more precise overcurrent control.
Optional external capacitors placed on the CTH and CTL pins
may be used to individually control the current shutdown duty
cycles from approximately 20% to <1%. Duty cycles from
20% to about 75% are possible with individual pull-up resistors from CTL and CTH to VDD. An open collector output
provides a fault indication when either sense input is tripped.
The MIC5022 is available in 16-pin wide SOIC and 14-pin
plastic DIP packages.
Other members of the MIC502x family include the MIC5020
low-side driver and the MIC5021 high-side driver.
•
•
•
•
•
•
•
•
•
•
12V to 36V operation
600ns rise time into 1000pF (high side)
TTL compatible input with internal pull-down resistor
Outputs interlocked to prevent cross conduction
TTL compatible enable
Fault output indication
Individual overcurrent limits
Gate protection
Internal charge pump (high-side)
Current source drive scheme reduces EMI
Applications
• Motor control
• Switch-mode power supplies
Ordering Information
Part Number
Temperature Range
Package
MIC5022BWM
–40°C to +85°C
16-pin Wide SOIC
MIC5022BN
–40°C to +85°C
14-pin Plastic DIP
Typical Application
+12V to +36V
1
10µF
TTL Input
(PWM signal)
2
3
4
CTH
5
6
CTL
7
MIC5022
VDD
VBOOST
Input
Gate H
Fault Sense H–
CTH
Sense H+
Enable
Gate L
CTL
Sense L–
Gnd
Sense L+
14
13
2.7nF
12
11
RS1
M
10
9
8
RS2
DC Motor Control Application
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MIC5022
Micrel
Pin Configuration
1 VDD
VBOOST 14
1
VDD
NC 16
2 Input
Gate H 13
2
NC
VBOOST 15
3 Fault
Sense H– 12
3
Input
Gate H 14
4 CTH
Sense H+ 11
4
Fault Sense H– 13
Gate L 10
5
CTH
6 CTL
Sense L– 9
6
Enable
7 Gnd
Sense L+ 8
7
CTL
Sense L– 10
8
Gnd
Sense L+ 9
5 Enable
DIP Package
(N)
Sense H+ 12
Gate L 11
SOIC Package
(WM)
Pin Description
DIP Pin No.
SOIC Pin No.
Pin Name
1
1
VDD
Supply: +12V to +36V. Decouple with ≥ 10µF capacitor.
2
3
Input
TTL Compatible Input: Logic high turns the high-side external MOSFET on
and the low-side external MOSFET off. Logic low turns the high-side
external MOSFET off and the low-side external MOSFET on. An internal
pull-down returns an open pin to logic low.
3
4
Fault
When either sense voltage exceeds threshold, open collector output is open
circuit for 5µs (tG(ON)), then pulled low for tG(OFF). tG(OFF) is adjustable from
CT.
4
5
CTH
Retry Trimming Capacitor, High Side: Controls the off time (tG(OFF)) of the
overcurrent retry cycle. (Duty cycle adjustment.)
• Open = approx. 20% duty cycle.
• Capacitor to Ground = approx. 20% to < 1% duty cycle.
• Pullup resistor = approx. 20% to approx. 75% duty cycle.
• Ground = maintained shutdown upon overcurrent condition.
5
6
Enable
6
7
CTL
Retry Trimming Capacitor, Low Side: Same function as CTH.
7
8
Gnd
Circuit Ground
8
8
Sense L +
Current Sense Comparator (+) Input, Low Side: Connect to source of lowside MOSFET. A built-in offset (nominal 50mV) in conjunction with RSENSE
sets the load overcurrent trip point.
9
10
Sense L –
Current Sense Comparator (–) Input, Low Side: Connect to the negative
side of the low-side sense resistor.
10
11
Gate L
Gate Drive, Low Side: Drives the gate of an external power MOSFET. Also
limits VGS to 15V max. to prevent Gate to Source damage. Will sink and
source current.
11
12
Sense H +
Current Sense Comparator (+) Input, High Side: Connect to source of highside MOSFET. A built-in offset (nominal 50mV) in conjunction with RSENSE
sets the load overcurrent trip point.
12
13
Source H –
Current Sense Comparator (–) Input, High Side: Connect to the negative
side of the high-side sense resistor.
13
14
Gate H
Gate Drive, High Side: Drives the gate of an external power MOSFET. Also
limits VGS to 15V max. to prevent Gate to Source damage. Will sink and
source current.
14
15
VBOOST
Charge Pump Boost Capacitor: A bootstrap capacitor from VBOOST to the
MOSFET source pin supplies charge to quickly enhance the external
MOSFET’s gate .
September 1999
Pin Function
Output Enable: Disables operation of the output drivers; active high. An
internal pull-down returns an open pin to logic low.
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MIC5022
MIC5022
Micrel
Block Diagram
6V Internal Regulator
I1
Fault
CINT
2I1
CTH
VDD
Normal
Sense H+
CHARGE
PUMP
Q1
Sense H–
VBOOST
1.4V
50mV
15V
ON
Input
OFF
↑ ONE↓ SHOT
10I2
6V
I2
Gate H
6V
I1
Fault
CTL
CINT
2I1
Normal
Sense L+
Fault
Q1
Sense L–
50mV
VDD
15V
ON
1.4V
OFF
↑ ONE↓ SHOT
10I2
I2
6V
Gate L
Enable
Transistor Count: 188
Absolute Maximum Ratings
Operating Ratings
Supply Voltage (VDD) .................................................. +40V
Input Voltage .................................................. –0.5V to 15V
Sense Differential Voltage .......................................... ±6.5V
Sense + or Sense – to Gnd .......................... –0.5V to +36V
Fault Voltage ............................................................... +36V
Current into Fault ....................................................... 50mA
Timer Voltage (CT) ..................................................... +5.5V
VBOOST Capacitor .................................................... 0.01µF
Supply Voltage (VDD) .................................... +12V to +36V
Temperature Range
SOIC ...................................................... –40°C to +85°C
PDIP ....................................................... –40°C to +85°C
MIC5022
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MIC5022
Micrel
Electrical Characteristics
TA = 25°C, Gnd = 0V, VDD = 12V, Gate CL = 1500pF (IRF540 MOSFET) unless otherwise specificed
Symbol
Parameter
Condition
Min
D.C. Supply Current
Typ
Max
Units
VDD = 12V, Input = 0V
2.5
5
mA
VDD = 36V, Input = 0V
6.0
10
mA
VDD = 12V, Input = 5V
2.4
5
mA
VDD = 36V, Input = 5V
3.0
25
mA
1.4
2.0
V
Input Threshold
0.8
Input Hysteresis
Input Pull-Down Current
0.1
Input = 5V
Enable Threshold
V
10
20
40
µA
0.8
1.4
2.0
V
Enable Hysteresis
0.1
Fault Output
Saturation Voltage
Fault Current = 1.6mA
Note 1
Fault Output Leakage
Fault = 36V
Current Limit Thresh., Low-Side
V
0.15
0.4
V
–1
0.01
+1
µA
Note 2
30
50
70
mV
Current Limit Thresh., High-Side
Note 2
30
50
70
mV
Gate On Voltage, High-Side
VDD = 12V, Note 3
16
18
21
V
VDD = 36V, Note 3
46
49
52
V
VDD = 12V, Note 3
10
11
VDD = 36V, Note 3
14
15
18
V
Gate On Voltage, Low-Side
V
tG(ON)
Gate On Time, Fixed
Sense Differential > 70mV
2
5
10
µs
tG(OFF)
Gate Off Time, Adjustable
Sense Differential > 70mV, CT = 0pF
10
20
50
µs
tDLH
Gate Turn-On Delay, High-Side
Note 4
1.4
2.0
µs
tR
Gate Rise Time, High-Side
Note 5
0.8
1.5
µs
tDHL
Gate Turn-Off Delay, High-Side
Note 6
1.2
2.0
µs
tF
Gate Fall Time, High-Side
Note 7
0.6
1.5
µs
tDLH
Gate Turn-On Delay, Low-Side
Note 4
1.7
2.5
µs
tR
Gate Rise Time, Low-Side
Note 8
0.7
1.5
µs
tDHL
Gate Turn-Off Delay, Low-Side
Note 9
0.5
1.0
µs
tF
Gate Fall Time, Low-Side
Note 10
1.0
1.5
µs
Note 1
Voltage remains low for time affected by CT.
Note 2
When using sense MOSFETs, it is recommended that RSENSE < 50Ω. Higher values may affect the sense MOSFET’s current transfer ratio.
Note 3
DC measurement.
Note 4
Input switched from 0.8V (TTL low) to 2.0V (TTL high), time for Gate transition from 0V to 2V.
Note 5
Input switched from 0.8V (TTL low) to 2.0V (TTL high), time for Gate transition from 2V to 17V.
Note 6
Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 20V (Gate on voltage) to 17V.
Note 7
Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 17V to 2V.
Note 8
Input switched from 0.8V (TTL low) to 2.0V (TTL high), time for Gate transition from 2V to 10V.
Note 9
Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 15V (Gate on voltage) to 10V.
Note 10 Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 10V to 2V.
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MIC5022
MIC5022
Micrel
Typical Characteristics
6.0
5.5
5.0
25
2.5
20
2.0
4.0
3.5
15
10
VIN = 5V
5
10
15
20 25 30
VSUPPLY (V)
35
5
0
40
5
2.5
1.5
VGATE H = VSUPPLY + 10V
CL = CH = 1500pF
CBOOST = 0.01µF
0.5
0
tON (µS)
tON 10V (µS)
2
5
10
15
20 25 30
VSUPPLY (V)
35
20
15
HIGH SIDE
NOTE:
tON, tOFF TIME
INDEPENDENT
OF VSUPPLY
1
10
100
CTH (pF)
1000 10000
RETRY DUTY CYCLE (%)
RETRY DUTY CYCLE (%)
35
0.0
40
5
10
15
20 25 30
VSUPPLY (V)
3.5
VGATE L = 4V
3.0 CL = CH
VSUPPLY = 12V
2.0
1.5
PROP.
DELAY
LOW-SIDE
2.0
NOTE: INCLUDES
PROPAGATION
DELAY & CROSS
CONDUCTION
LOCKOUT
PROP.
DELAY
1.0
1x100 1x101 1x102 1x103 1x104 1x105
CGATE (pF)
Input Current vs.
Input Voltage
100
VSUPPLY = 12V
20.0
tON = 5µS
VSUPPLY = 12V
80
15.0
LOW SIDE
60
40
20
5.0
0.0
0.1
40
2.5
1.5
NOTE: INCLUDES PROPAGATION
DELAY & CROSS CONDUCTION
LOCKOUT
10.0
35
Gate Turn-On/Off Delay vs.
Gate Capacitance
4.5 VGATE H = VSUPPLY + 4V
4.0 CL = CH
VSUPPLY = 12V
3.5
3.0
HIGH-SIDE
2.5
25.0
tON = 5µS
VSUPPLY = 12V
0
0.1
20 25 30
VSUPPLY (V)
Overcurrent Retry Duty
Cycle vs. Timing Capacitance
25
5
15
0.0
1x100 1x101 1x102 1x103 1x104 1x105
CGATE (pF)
40
Overcurrent Retry Duty
Cycle vs. Timing Capacitance
10
10
NOTE: INCLUDES PROPAGATION
DELAY & CROSS CONDUCTION
LOCKOUT
5.0
1.0
0.5
NOTE: INCLUDES PROPAGATION
DELAY & CROSS CONDUCTION
LOCKOUT
VGATE = VSUPPLY + 4V
CL = CH = 1500pF
CBOOST = 0.01µF
1.0
Gate Turn-On/Off Delay vs.
Gate Capacitance
Gate Turn-On Delay vs.
Supply Voltage
1
1.5
0.5
tON (µS)
2.0
IIN (µA)
3.0
2.5
tON 4V (µS)
4.5
1.5
1.0
Gate Turn-On Delay vs.
Supply Voltage
VIN = 0V
VGATE H (V)
ISUPPLY (mA)
Gate to Source Voltage
vs. Supply Voltage
Supply Current vs.
Supply Voltage
1
10
100
CTL (pF)
1000 10000
0
0
5
10
15
VIN (V)
20
25
Sense Threshold vs.
Temperature
80
VOLTAGE (mV)
70
60
50
40
30
20
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
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September 1999
MIC5022
Micrel
Input
Enable
Gate H
Gate L
TTL (H)
0V
TTL (H)
0V
15V (max.)
Source
15V (max.)
0V
Sense H+, H–
Differential
50mV
Sense L+, L–
Differential
50mV
0V
0V
Off
Fault
On
Timing Diagram 1. Normal Operation
20µs
5µs
Input
Enable
Gate H
Gate L
Sense H+, H–
Differential
Sense L+, L–
Differential
TTL (H)
0V
TTL (H)
0V
15V (max.)
0V
15V (max.)
0V
50mV
0V
50mV
0V
Off
Fault
On
Timing Diagram 2. Overcurrent Fault with Retry
5µs
Input
Enable
Gate H
Gate L
Sense H+, H–
Differential
Sense L+, L–
Differential
TTL (H)
0V
TTL (H)
0V
15V (max.)
Source
15V (max.)
0V
50mV
0V
50mV
0V
Off
Fault
On
Timing Diagram 3. Overcurrent Fault with Maintained Off
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MIC5022
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Micrel
Functional Description
cause it is on the high side of the load) raising the VBOOST pin
voltage. The boost capacitor charge is directed through the
gate pin to quickly charge the FET’s gate to 15V maximum
above VDD. The internal charge pump maintains the gate
voltage by supplying a small current as needed.
Overcurrent Limiting (High or Low-Side)
Current source I1 charges CINT upon power up. An optional
external capacitor connected to CT is kept discharged through
a FET Q1.
A fault condition (> 50mV from SENSE + to SENSE –) causes
the overcurrent comparator to enable current sink 2I1 which
overcomes current source I1 to discharge CINT in about 5µs
time. When CINT is discharged, the INPUT is disabled, the
FAULT output is enabled, and CINT and CT are ready to be
charged. Since the INPUT is disabled the GATE output turns
off.
When the GATE output turns off the FET, the overcurrent
signal is removed from the sense inputs which deactivates
current sink 2I1. This allows CINT and the optional capacitor
connected to CT to recharge. A Schmitt trigger delays the
retry while the capacitor(s) recharge. Retry delay is increased by connecting a capacitor connected to CT (optional).
The MIC5022’s low-side driver may be used without current
sensing by grounding both SENSE + and SENSE – pins. The
high-side driver may be used without current sensing by
connecting SENSE + and SENSE – to the source of the
external high-side MOSFET.
Fault Output
The FAULT output is an open collector transistor. FAULT is
active at approximately the same time the output is disabled
by a fault condition (5µs after an overcurrent condition is
sensed). The FAULT output is open circuit (off) during each
successive retry (5µs).
Refer to the MIC5022 block diagram.
Input
A signal greater than 1.4V (nominal) applied to the MIC5022
INPUT causes gate enhancement on an external MOSFET
connected to GATE H turning the high-side MOSFET on.
At the same time internal logic removes gate enhancement
from an external MOSFET connected to GATE L, turning the
low-side MOSFET off.
An internal pull-down resistor insures that an open INPUT
remains low, keeping the external high-side MOSFET turned
off and the low-side MOSFET turned on.
Enable (Active Low)
A signal greater than 1.4V (nominal) applied to the MIC5022
ENABLE keeps both GATE outputs off. An internal pull-down
resistor insures that the MIC5022 is enabled if the pin is open.
Gate Outputs
Rapid rise and fall times on the GATE output are possible
because each input state change triggers a one-shot which
activates a high-value current sink (10I2) for a short time. This
draws a high current though a current mirror circuit causing
the output transistors to quickly charge or discharge the
external FET’s gate.
A second current sink continuously draws the lower value of
current used to maintain the gate voltage for the selected
state.
Internal 15V Zener diodes protect the external high-side and
low-side MOSFETs by limiting the gate to source voltage.
Charge Pump (High-Side)
An internal charge pump utilizes an external “boost” capacitor
connected between VBOOST and the source of the external
FET (refer to Typical Application). The boost capacitor stores
charge when the FET is off. As the FET begins to turn on the
voltage on the source side of the capacitor increases (be-
Typical Full-Bridge Application
+12V to +20V
MIC5022
10µF
TTL Input
(PWM signal)
1
2
3
4
5
6
7
VDD
VBOOST
Input
Gate H
Fault Sense H–
CTH
Enable
Sense H+
Gate L
CTL
Sense L–
Gnd
Sense L+
MIC5022
14
13
12
11
14
0.01µF
0.01µF
Load
13
12
11
10
10
9
9
8
8
VBOOST
VDD
Gate H
Input
Sense H– Fault
Sense H+
Gate L
CTH
Enable
Sense L–
CTL
Sense L+
Gnd
1
10µF
2
TTL Input
(PWM signal)
3
4
5
6
7
Figure 1. Basic Full-Bridge Circuit
MIC5022
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September 1999
MIC5022
Micrel
Applications Information
Circuits Without Current Sensing
Current sensing may be omitted by connecting the high-side
SENSE + and SENSE – pins to the source of the MOSFET or
the supply and the low-side SENSE + and SENSE – pins to
ground. Do not connect the high-side sense pins to ground.
Inductive Load Precautions
Circuits controlling inductive loads require precautions when
controlled by the MIC5022. Wire wound resistors, which are
sometimes used to simulate other loads, can also show
significant inductive properties.
Sense Pin Considerations
The sense pins of the MIC5022 are sensitive to negative
voltages. If a voltage spike is too negative (below approximately –0.5V), current will be drawn from functional sections
of the IC resulting in unpredictable circuit behavior or damage. Resistors and Schottky diodes may be used to protect
the sense pins from the negative spikes. Refer to the
MIC5021 data sheet for details.
The MIC5022 MOSFET driver is designed for half-bridge
switching applications where overcurrent limiting and high
speed are required. The MIC5022 can control MOSFETs that
switch voltages up to 36V.
The MIC5022 functionally includes the MIC5020 and MIC5021
with additional circuitry to coordinate the operation of the high
and low-side drivers. Since most output considerations are
similar, refer to the MIC5020 and MIC5021 data sheets for
additional applications information.
Supply Voltage
The MIC5022’s supply input (VDD) is rated up to 36V. The
supply voltage must be equal to or greater than the voltage
applied to the drain of the external N-channel MOSFET.
A 16V minimum supply is recommended to produce continuous on-state, gate drive voltage for standard MOSFETs (10V
nominal gate enhancement).
When the driver is powered from a 12V to 16V supply, a logiclevel MOSFET is recommended (5V nominal gate enhancement).
PWM operation may produce satisfactory gate enhancement
at lower supply voltages. This occurs when fast switching
repetition makes the boost capacitor a more significant
voltage supply than the internal charge pump.
Overcurrent Limiting
Separate high and low-side 50mV comparators are provided
for current sensing. The low level trip point minimizes I2R
losses when a power resistor is used for current sensing.
The adjustable retry feature can be used to handle loads with
high initial currents, such as lamps or heating elements, and
can be adjusted from the CT connection.
CT to ground causes maintained gate drive shutdown following an overcurrent condition.
CT open, or a capacitor to ground, causes automatic retry.
The default duty cycle (CT open) is approximately 20% (the
high side is slightly greater than the low side). Refer to the
typical characteristics when selecting a capacitor for a reduced duty cycle.
CT through a pull-up resistor to VDD increases the duty cycle.
Increasing the duty cycle increases the power dissipation in
the load and MOSFET under a “fault” condition. Circuits may
become unstable at a duty cycle of about 75% or higher,
depending on conditions. Caution: The MIC5022 may be
damaged if the voltage applied to CT exceeds the absolute
maximum voltage rating.
Boost Capacitor Selection
For 12V to 20V operation, the boost capacitor should be
0.01µF; and for 12V to 36V operation, the boost capacitor
should be 2.7nF; both connected between VBOOST and the
MOSFET source. The preferred configuration for 20V to 36V
operation is a 0.1µF capacitor connected between VBOOST
and VDD . Refer to the MIC5021 data sheet for examples.
Do not connect capacitors between VBOOST and the MOSFET
source and between VBOOST and VDD at the same time.
Larger capacitors than specified may damage the MIC5022.
September 1999
High-Side Sensing
For the high-side driver, sensing the current on the supply
side of the high-side MOSFET locates the SENSE pins away
from the inductive spike. Refer to the MIC5021 data sheet for
details.
Low-Temperature Operation
As the temperature of the MIC5022AJB (extended temperature range version—no longer available) approaches –55°C,
the driver’s off-state, gate-output offset from ground increases. If the operating environment of the MIC5022AJB
includes low temperatures (–40°C to –55°C), add an external
2.2MΩ resistor from gate-to-source or from gate-to-ground.
This assures that the driver’s gate-to-source voltage is far
below the external MOSFET’s gate threshold voltage, forcing
the MOSFET fully off. Refer to the MIC5020 and MIC5021
data sheets for examples.
The gate-to-source configuration is appropriate for resistive
and inductive loads. This also causes the smallest decrease
in gate output voltage.
The gate-to-ground configuration is appropriate for resistive,
inductive, or capacitive loads. This configuration will decrease the gate output voltage slightly more than the gate-tosource configuration.
Full-Bridge Motor Control
An application for two MIC5022s is the full-bridge motor
control circuit.
Two high or two low-side sense inputs may be used for
overcurrent detection. (Low-side sensing is shown in Figure 2). Sensing at four locations is usually unnecessary.
When switching inductive loads, such as motors, it is desirable to place the high-side sense inputs on the supply side of
the MOSFETs. The helps prevent the inductive spikes that
occur upon load shutoff from affecting the sense inputs.
185
MIC5022
MIC5022
Micrel
+12V to +20V
MIC5022
10µF
1
TTL Input
(PWM signal)
2
3
4
5
6
7
MIC5022
VDD
VBOOST
Input
Gate H
Fault Sense H–
CTH
Sense H+
Gate L
Enable
Sense L–
CTL
Sense L+
Gnd
14
14
13
13
12
12
11
0.01µF
0.01µF
M
10
11
10
9
9
RS2
RS1
8
8
VBOOST
VDD
Gate H
Input
Sense H– Fault
Sense H+
Gate L
CTH
Enable
Sense L–
CTL
Sense L+
Gnd
1
10µF
2
TTL Input
(PWM signal)
3
4
5
6
7
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
470µF
25V
13k
0.1µF
47k
300k
0.15µF
5
2
MIC38C43
4.7nF 1
4.3k
2
3
4
3.3k
2200pF
MIC5022
1
Comp
VREF
FB
VDD
IS
VOUT
RT/CT
Gnd
8
8
7
9
6
7
5
V+
0.1µF
Gate H
14
Enable
VPP
Input
Gate L
S L+
S H+
12
S H–
Gnd
Fault
Q1
5mΩ
70µH
VOUT
5V, 8A
10
11
S L–
SMP06N06-14
13
Q2
1000µF
Low ESR
3
10k
Figure 3. 50kHz Synchronous Rectifier Converter
MIC5022
186
September 1999