MIC5011 [MICREL]
Minimum Parts High- or Low-Side MOSFET Driver; 最小的零件高或低侧MOSFET驱动器
| 型号： | MIC5011 |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | Minimum Parts High- or Low-Side MOSFET Driver |
| 文件： | 总12页 (文件大小：124K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC5011
Minimum Parts High- or Low-Side MOSFET Driver
General Description
Features
The MIC5011 is the “minimum parts count” member of the
Micrel MIC501X driver family. These ICs are designed to
drive the gate of an N-channel power MOSFET above the
supplyrailinhigh-sidepowerswitchapplications. The8-pin
MIC5011 is extremely easy to use, requiring only a power
FET and nominal supply decoupling to implement either a
high- or low-side switch.
• 4.75V to 32V operation
• Less than 1µA standby current in the “off” state
• Internal charge pump to drive the gate of an N-channel
power FET above supply
• Available in small outline SOIC packages
• Internal zener clamp for gate protection
• Minimum external parts count
• Can be used to boost drive to low-side power FETs
operating on logic supplies
• 25µs typical turn-on time with optional external
capacitors
The MIC5011 charges a 1nF load in 60µs typical with no
external components. Faster switching is achieved by add-
ing two 1nF charge pump capacitors. Operation down to
4.75V allows the MIC5011 to drive standard MOSFETs in
5V low-side applications by boosting the gate voltage
above the logic supply. In addition, multiple paralleled
MOSFETs can be driven by a single MIC5011 for ultra-high
current applications.
• Implements high- or low-side drivers
Applications
• Lamp drivers
Other members of the Micrel driver family include the
MIC5012 dual driver and MIC5013 protected 8-pin driver.
• Relay and solenoid drivers
• Heater switching
• Power bus switching
For new designs, Micrel recommends the pin-compatible
MIC5014 MOSFET driver.
Typical Applications
Ordering Information
Part Number
MIC5011BN
MIC5011BM
Temp. Range
Package
14.4V
–40°C to +85°C 8-pin Plastic DIP
–40°C to +85°C 8-pin SOIC
ON
+
MIC5011
10µF
8
7
6
5
1
2
3
4
V+
C1
Control Input
Input
Source
Gnd
Com
C2
Gate
IRF531
#6014
OFF
Figure 1. High Side Driver
Note: The MIC5011 is ESD sensitive.
5V
48V
ON
10µF
+
MIC5011
8
7
6
5
1
2
3
4
V+
C1
100W
Input
Source
Gnd
Com
C2
Control Input
Heater
Gate
IRF530
Protected under one or more of the following Micrel patents:
patent #4,951,101; patent #4,914,546
OFF
Figure 2. Low Side Driver
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
July 2000
1
MIC5011
MIC5011
Micrel
Absolute Maximum Ratings (Note 1, 2)
Operating Ratings (Notes 1, 2)
Power Dissipation
+
Supply Voltage (V ), Pin 1
Input Voltage, Pin 2
Source Voltage, Pin 3
Current into Pin 3
–0.5V to 36V
–10V to V
–10V to V
50mA
–1V to 50V
150°C
1.25W
100°C/W
170°C/W
+
+
θ
θ
(Plastic DIP)
(SOIC)
JA
JA
Ambient Temperature: B version
Storage Temperature
Lead Temperature
–40°C to +85°C
–65°C to +150°C
260°C
Gate Voltage, Pin 5
Junction Temperature
(Soldering, 10 seconds)
+
Supply Voltage (V ), Pin 1
4.75V to 32V high side
4.75V to 15V low side
Pin Description (Refer to Typical Applications)
Pin Number
Pin Name
Pin Function
1
V+
Supply; must be decoupled to isolate from large transients caused by the
power FET drain. 10µF is recommended close to pins 1 and 4.
2
3
Input
Turns on power MOSFET when taken above threshold (3.5V typical).
Requires <1 µA to switch.
Source
Connects to source lead of power FET and is the return for the gate clamp
zener. Can safely swing to –10V when turning off inductive loads.
4
5
Ground
Gate
Drives and clamps the gate of the power FET. Will be clamped to approxi-
mately –0.7V by an internal diode when turning off inductive loads.
6, 7, 8
C2, Com, C1
Optional 1nF capacitors reduce gate turn-on time; C2 has dominant effect.
Pin Configuration
MIC5011
1
2
3
4
8
7
6
5
C1
Com
C2
V+
Input
Source
Gnd
Gate
MIC5011
2
July 2000
MIC5011
Micrel
Electrical Characteristics (Note 3) Test circuit. TA = –55°C to +125°C, V+ = 15V, all switches open, unless
otherwise specified.
Parameter
Conditions
Min Typical Max
Units
Supply Current, I1
V+ = 32V
VIN = 0V, S2 closed
VIN = V+ = 32V
0.1
8
10
20
4
µA
mA
mA
V
V+ = 5V
VIN = 5V, S2 closed
Adjust VIN for VGATE low
Adjust VIN for VGATE high
Adjust VIN for VGATE high
VIN = 0V
1.6
Logic Input Voltage
V+ = 4.75V
2
4.5
5.0
–1
V
V+ = 15V
V+ = 32V
V
Logic Input Current, I2
µA
µA
pF
V
VIN = 32V
1
Input Capacitance
Gate Drive, VGATE
Pin 2
5
10
S1, S2 closed,
VS = V+, VIN = 5V
S2 closed, VIN = 5V
V+ = 4.75V, IGATE = 0, VIN = 4.5V
V+ = 15V, IGATE = 100µA, VIN = 5V
V+ = 15V, VS = 15V
7
24
11
11
27
V
Zener Clamp,
12.5
13
15
16
50
V
VGATE – VSOURCE
V+ = 32V, VS = 32V
V
Gate Turn-on Time, tON
(Note 4)
VIN switched from 0 to 5V; measure time
for VGATE to reach 20V
25
µs
Gate Turn-off Time, tOFF
VIN switched from 5 to 0V; measure time
for VGATE to reach 1V
4
10
µs
Note 1 Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when
operating the device beyond its specified Operating Ratings.
Note 2 The MIC5011 is ESD sensitive.
Note 3 Minimum and maximum Electrical Characteristics are 100% tested at T = 25°C and T = 85°C, and 100% guaranteed over the entire
A
A
range. Typicals are characterized at 25°C and represent the most likely parametric norm.
Note 4 Test conditions reflect worst case high-side driver performance. Low-side and bootstrapped topologies are significantly faster—see
Applications Information. Maximum value of switching speed seen at 125°C, units operated at room temperature will reflect the typical
values shown.
Test Circuit
V+
+
1µF
MIC5011
1
2
3
4
8
7
6
5
V+
C1
Com
C2
1nF
1nF
Input
Source
Gnd
VGATE
VIN
500Ω
1W
Gate
1nF
S1
S2
I5
VS
July 2000
3
MIC5011
MIC5011
Micrel
Typical Characteristics (Continued)
DC Gate Voltage
above Supply
Supply Current
12
14
12
10
8
10
8
6
6
4
4
2
0
2
0
0
5
10 15 20 25 30 35
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
High-side Turn-on Time*
High-side Turn-on Time*
350
300
250
200
150
100
50
140
120
100
80
C
=1 nF
GATE
C
GATE
=1 nF
C2=1 nF
60
40
20
0
0
0
3
6
9
12
15
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
High-side Turn-on Time*
High-side Turn-on Time*
3.5
3.0
2.5
2.0
1.5
1.0
0.5
1.4
1.2
1.0
0.8
0.6
0.4
0.2
C
=10 nF
GATE
C
GATE
=10 nF
C2=1 nF
0
0
0
3
6
9
12
15
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
+
+
* Time for gate to reach V + 5V in test circuit with VS = V – 5V.
MIC5011
4
July 2000
MIC5011
Micrel
Typical Characteristics (Continued)
Low-side Turn-on Time
for Gate = 5V
Low-side Turn-on Time
for Gate = 5V
1000
1000
300
100
30
C2=1 nF
300
C
GATE
=10 nF
C
GATE
=10 nF
100
30
10
3
10
C
GATE
=1 nF
C
GATE
=1 nF
3
1
1
0
3
6
9
12
15
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Low-side Turn-on Time
for Gate = 10V
Low-side Turn-on Time
for Gate = 10V
3000
1000
300
100
30
3000
1000
300
100
30
C2=1 nF
C
GATE
=10 nF
C
GATE
=10 nF
C
GATE
=1 nF
C
GATE
=1 nF
10
10
3
0
3
3
6
9
12
15
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Turn-on Time
Turn-off Time
2.0
1.75
1.5
50
40
C
GATE
=10 nF
30
20
1.25
1.0
C
=1 nF
12
10
GATE
0.75
0.5
0
0
3
6
9
15
–25
0
25
50 75 100 125
SUPPLY VOLTAGE (V)
DIE TEMPERATURE (°C)
July 2000
5
MIC5011
MIC5011
Micrel
Charge Pump
Charge Pump
Output Current
Output Current
250
200
150
100
50
1.0
0.8
+
V
=V
GATE
+
V
=V
GATE
0.6
0.4
+
V
=V +5V
GATE
+
=V +5V
V
GATE
0.2
0
C2=1 nF
VS=V –5V
+
VS=V –5V
+
0
0
5
10
15 20 25
30
0
5
10
15 20 25
30
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Block Diagram
Ground V+
C1 Com C2
1
8
7
6
4
MIC5011
CHARGE
PUMP
5 Gate
500Ω
12.5V
Source
LOGIC
2
Input
3
Applications Information
Functional Description (Refer to Block Diagram)
The charge pump incorporates a 100kHz oscillator and on-
chip pump capacitors capable of charging 1nF to 5V above
supply in 60µs typical. With the addition of 1nF capacitors
at C1 and C2, the turn-on time is reduced to 25µs typical
(see Figure 3). The charge pump is capable of pumping the
gate up to over twice the supply voltage. For this reason, a
zener clamp (12.5V typical) is provided between the gate
The MIC5011 functions are controlled via a logic block
connected to the input pin 2. When the input is low, all
functions are turned off for low standby current and the gate
of the power MOSFET is also held low through 500Ω to an
N-channel switch. When the input is taken above the turn-
on threshold (3.5V typical), the N-channel switch turns off
and the charge pump is turned on to charge the gate of the
power FET.
pin 5 and source pin 3 to prevent exceeding the V rating
GS
of the MOSFET at high supplies.
MIC5011
6
July 2000
MIC5011
Micrel
Applications Information (Continued)
atgroundpotential. TheMOSFETisforcedintoconduction,
Construction Hints
and it dissipates the energy stored in the load inductance.
The MIC5011 source pin (3) is designed to withstand this
negativeexcursionwithoutdamage. Externalclampdiodes
are unnecessary.
High current pulse circuits demand equipment and assem-
bly techniques that are more stringent than normal, low
current lab practices. The following are the sources of
pitfalls most often encountered during prototyping. Sup-
plies: many bench power supplies have poor transient
response. Circuits that are being pulse tested, or those that
operate by pulse-width modulation will produce strange
results when used with a supply that has poor ripple
rejection, or a peaked transient response. Always monitor
thepowersupplyvoltagethatappearsatthedrainofahigh-
sidedriver(orthesupplysideoftheloadinalow-sidedriver)
with an oscilloscope. It is not uncommon to find bench
power supplies in the 1 kW class that overshoot or under-
shoot by as much as 50% when pulse loaded. Not only will
theloadcurrentandvoltagemeasurementsbeaffected,but
it is possible to over-stress various components—espe-
cially electrolytic capacitors—with possibly catastrophic
results. A 10µF supply bypass capacitor at the chip is
recommended.
Low-Side Driver (Figure 2). A key advantage of the low-
side topology is that the load supply is limited only by the
MOSFET BVDSS rating. Clamping may be required to
protect the MOSFET drain terminal from inductive switch-
ing transients. The MIC5011 supply should be limited to
15V in low-side topologies, otherwise a large current will be
forced through the gate clamp zener.
Low-side drivers constructed with the MIC501X family are
also fast; the MOSFET gate is driven to near supply
immediatelywhencommandedON.Typicalcircuitsachieve
10V enhancement in 10µs or less on a 12 to 15V supply.
Modifying Switching Times (Figure 3). High-side switch-
ingtimescanbeimprovedbyafactorof2ormorebyadding
external charge pump capacitors of 1nF each. In cost-
sensitiveapplications,omitC1(C2hasadominanteffecton
speed).
Residual Resistances: Resistances in circuit connections
may also cause confusing results. For example, a circuit
may employ a 50mΩ power MOSFET for low drop, but
careless construction techniques could easily add 50 to
100mΩ resistance. Do not use a socket for the MOSFET. If
the MOSFET is a TO-220 type package, make high-current
drain connections to the tab. Wiring losses have a profound
effect on high-current circuits. A floating millivoltmeter can
identify connections that are contributing excess drop un-
der load.
Do not add external capacitors to the MOSFET gate. Add a
resistor (1kΩ to 51kΩ) in series with the gate to slow down
the switching time.
14.4V
ON
+
MIC5011
10µF
8
7
6
5
1
2
3
4
V+
C1
1nF
1nF
Input
Source
Gnd
Com
C2
Control Input
Circuit Topologies
The MIC5011 is suited for use with standard MOSFETs in
high-orlow-sidedriverapplications.Inaddition,theMIC5011
works well in applications where, for faster switching times,
the supply is bootstrapped from the MOSFET source out-
put.Lowvoltage,high-sidedrivers(suchasshowninFigure
1) are the slowest; their speed is reflected in the gate turn-
on time specifications. The fastest drivers are the low-side
and bootstrapped high-side types (Figures 2 and 4). Load
current switching times are often much faster than the time
to full gate enhancement, depending on the circuit type, the
MOSFET, and the load. Turn-off times are essentially the
Gate
IRF531
OFF
LOAD
Figure 3. High Side Driver with
External Charge Pump Capacitors
Bootstrapped High-Side Driver (Figure 4). The speed of
a high-side driver can be increased to better than 10µs by
bootstrapping the supply off of the MOSFET source. This
topology can be used where the load is pulse-width modu-
lated (100Hz to 20kHz), or where it is energized continu-
ously. The Schottky barrier diode prevents the MIC5011
supply pin from dropping more than 200mV below the drain
supply, and it also improves turn-on time on supplies of less
than 10V. Since the supply current in the “off” state is only
a small leakage, the 100nF bypass capacitor tends to
remain charged for several seconds after the MIC5011 is
turnedoff.InaPWMapplicationthechipsupplyissustained
at a higher potential than the system supply, which im-
proves switching time.
sameforallcircuits(lessthan10µstoV =1V).Thechoice
GS
of one topology over another is based on a combination of
considerations including speed, voltage, and desired sys-
tem characteristics.
High-Side Driver (Figure 1). The high-side topology works
+
well down to V = 7V with standard MOSFETs. From 4.75
to 7V supply, a logic-level MOSFET can be substituted
since the MIC5011 will not reach 10V gate enhancement
(10Visthemaximumratingforlogic-compatibleMOSFETs).
High-side drivers implemented with MIC501X drivers are
self-protected against inductive switching transients. Dur-
ing turn-off an inductive load will force the MOSFET source
5Vormorebelowground, whiletheMIC5011holdsthegate
July 2000
7
MIC5011
MIC5011
Micrel
Applications Information (Continued)
7 to 15V
1N5817
1N4001 (2)
100nF
+
15V
10µF
MIC5011
33kΩ
1
2
3
4
8
7
6
5
33pF
V+
C1
Com
C2
To MIC5011
Input
100kΩ
Control Input
Input
Source
Gnd
MPSA05
4N35
Gate
IRF540
10mA
Control Input
100kΩ
1kΩ
LOAD
Figure 5. Improved
Opto-Isolator Performance
Figure 4. Bootstrapped
High-Side Driver
Opto-Isolated Interface (Figure 5). Although the MIC5011
has no special input slew rate requirement, the lethargic
transitions provided by an opto-isolator may cause oscilla-
tions on the rise and fall of the output. The circuit shown
accelerates the input transitions from a 4N35 opto-isolator
by adding hysteresis. Opto-isolators are used where the
control circuitry cannot share a common ground with the
MIC5011 and high-current power supply, or where the
control circuitry is located remotely. This implementation is
intrinsically safe; if the control line is severed the MIC5011
will turn OFF.
ible with control boxes such as the CR2943 series (GE).
The circuit is configured so that if both switches close
simultaneously, the “off” button has precedence.
Thisapplicationalsoillustrateshowtwo(ormore)MOSFETs
canbeparalleled. Thisreducestheswitchdrop, anddistrib-
utes the switch dissipation into multiple packages.
High-VoltageBootstrap(Figure7).AlthoughtheMIC5011
is limited to operation on 4.75 to 32V supplies, a floating
bootstrap arrangement can be used to build a high-side
switchthatoperatesonmuchhighervoltages.TheMIC5011
and MOSFET are configured as a low-side driver, but the
load is connected in series with ground.
Industrial Switch (Figure 6). The most common manual
control for industrial loads is a push button on/off switch.
The “on” button is physically arranged in a recess so that in
apanicsituationthe“off”button, whichextendsoutfromthe
control box, is more easily pressed. This circuit is compat-
Power for the MIC5011 is supplied by a charge pump. A
20kHz square wave (15Vp-p) drives the pump capacitor
and delivers current to a 100µF storage capacitor. A zener
24V
+
10µF
100kΩ
MIC5011
1
8
7
6
5
ON
V+
C1
Com
C2
CR2943-NA102A
(GE)
2
3
4
Input
Source
Gnd
OFF
Gate
IRFP044 (2)
330kΩ
LOAD
Figure 6. 50-Ampere
Industrial Switch
MIC5011
8
July 2000
MIC5011
Micrel
Applications Information (Continued)
15V
+
100µF
90V
1N4746
MIC5011
1
2
3
4
8
33kΩ
V+
C1
Com
C2
1N4003 (2)
33pF
7
6
5
Input
Source
Gnd
MPSA05
100kΩ
1nF
Gate
IRFP250
4N35
10mA
Control Input
100kΩ
1kΩ
1/4 HP, 90V
5BPB56HAA100
(GE)
M
100nF
200V
1N4003
15Vp-p, 20kHz
Squarewave
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.
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.
ThecircuitofFigure8utilizesfastconfigurationsforboththe
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 to-
gether to form an H-bridge for locked antiphase or sign/
magnitude control.
Half-BridgeMotorDriver(Figure8).Closedloopcontrolof
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.
15V
1N5817
1N4001 (2)
100nF
+
1N4148
MIC5011
1
2
3
4
8
7
6
5
1µF
V+
C1
Com
C2
Input
Source
Gnd
220pF
22kΩ
Gate
IRF541
PWM
INPUT
15V
+
12V,
10A Stalled
M
10µF
MIC5011
8
7
6
5
1
2
3
4
V+
C1
10kΩ
Input
Source
Gnd
Com
C2
22kΩ
1nF
Gate
IRF541
2N3904
Figure 8. Half-Bridge
Motor Driver
July 2000
9
MIC5011
MIC5011
Micrel
Applications Information (Continued)
12V
12V
+
10µF
MIC5011
8
1
2
3
4
+
10µF
V+
C1
MIC5011
7
6
5
Input
Source
Gnd
Com
C2
1
2
3
4
8
7
6
5
V+
C1
Com
C2
R
100kΩ
1N4148
Input
Source
Gnd
330kΩ
330kΩ
Gate
IRFZ44
+
47µF
IRFZ44
Gate
1N4148
10kΩ
100nF
100Ω
OUTPUT
(Delay=2.5s)
M
T
12V
START
RUN
Figure 9. 30 Ampere
Time-Delay Relay
STOP
Time-Delay Relay (Figure 9). The MIC5011 forms the
basis of a simple time-delay relay. As shown, the delay
commenceswhenpowerisapplied, butthe100kΩ/1N4148
couldbeindependentlydrivenfromanexternalsourcesuch
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.
Figure 10. Motor Stall
Shutdown
Motor Driver with Stall Shutdown (Figure 10). 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 MIC5011 input ON. If the motor slows down, the tach
output is reduced, and the MIC5011 switches OFF. Resis-
tor “R” sets the shutdown threshold.
15V
Electronic Governor (Figure 11). The output of an ac
tachometercanbeusedtoformaPWMlooptomaintainthe
speed of a motor. The tachometer output is rectified,
partially filtered, and fed back to the input of the MIC5011.
When the motor is stalled there is no tachometer output,
and MIC5011 input is pulled high delivering full power to the
motor.Ifthemotorspinsfastenough,thetachometeroutput
is sufficient to pull the MIC5011 input low, shutting the
output off. Since the rectified waveform is only partially
filtered, the input oscillates around its threshold causing the
MIC5011 to switch on and off at the frequency of the
tachometer signal. A PWM action results since the average
dc voltage at the input decreases as the motor spins faster.
The 1kΩ potentiometer is used to set the running speed of
themotor. Loopgain(andspeedregulation)isincreasedby
increasing the value of the 100nF filter capacitor.
+
10µF
MIC5011
330kΩ
8
7
6
5
1
2
3
4
V+
C1
330kΩ
Input
Source
Gnd
1nF
Com
C2
Gate
IRF541
1N4148
100nF
M
T
15V
1kΩ
Theperformanceofsuchaloopisimprecise, butstableand
inexpensive.AmoreelaborateloopwouldconsistofaPWM
controller and a half-bridge.
Figure 11. Electronic Governor
MIC5011
10
July 2000
MIC5011
Micrel
ON. C1 is discharged, and C2 is charged to supply through
Applications Information (Continued)
Q5. For the second phase Q4 turns off and Q3 turns on,
pushing pin C2 above supply (charge is dumped into the
gate). Q3 also charges C1. On the third phase Q2 turns off
and Q1 turns on, pushing the common point of the two
capacitors above supply. Some of the charge in C1 makes
its way to the gate. The sequence is repeated by turning Q2
and Q4 back on, and Q1 and Q3 off.
Gate Control Circuit
When applying the MIC5011, it is helpful to understand the
operation of the gate control circuitry (see Figure 12). The
gate circuitry can be divided into two sections: 1) charge
pump (oscillator, Q1-Q5, and the capacitors) and 2) gate
turn-off switch (Q6).
In a low-side application operating on a 12 to 15V supply,
theMOSFETisfullyenhancedbytheactionofQ5alone.On
supplies of more than approximately 14V, current flows
directly from Q5 through the zener diode to ground. To
prevent excessive current flow, the MIC5011 supply should
be limited to 15V in low-side applications.
When the MIC5011 is in the OFF state, the oscillator is
turned off, thereby disabling the charge pump. Q5 is also
turned off, and Q6 is turned on. Q6 holds the gate pin (G) at
ground potential which effectively turns the external MOS-
FET off.
Q6 is turned off when the MIC5011 is commanded on, and
Q5 pulls the gate up to supply (through 2 diodes). Next, the
chargepumpbeginssupplyingcurrenttothegate. Thegate
acceptschargeuntilthegate-sourcevoltagereaches12.5V
and is clamped by the zener diode.
The action of Q5 makes the MIC5011 operate quickly in
low-side applications. In high-side applications Q5
prechargestheMOSFETgatetosupply, leavingthecharge
pump to carry the gate up to full enhancement 10V above
supply. Bootstrapped high-side drivers are as fast as low-
side drivers since the chip supply is boosted well above the
drain at turn-on.
A 2-output, three-phase clock switches Q1-Q4, providing a
quasi-tripling action. During the initial phase Q4 and Q2 are
+
V
Q5
Q3
Q1
125pF
125pF
C2
C1
COM
C1
C2
Q2
Q4
G
S
100 kHz
OSCILLATOR
500Ω
GATE CLAMP
ZENER
12.5V
OFF
ON
Q6
Figure 12. Gate Control
Circuit Detail
July 2000
11
MIC5011
MIC5011
Micrel
Package Information
PIN 1
DIMENSIONS:
INCH (MM)
0.380 (9.65)
0.370 (9.40)
0.255 (6.48)
0.245 (6.22)
0.135 (3.43)
0.125 (3.18)
0.300 (7.62)
0.013 (0.330)
0.010 (0.254)
0.380 (9.65)
0.320 (8.13)
0.018 (0.57)
0.100 (2.54)
0.130 (3.30)
0.0375 (0.952)
8-Pin Plastic DIP (N)
0.026 (0.65)
MAX)
PIN 1
0.157 (3.99)
0.150 (3.81)
DIMENSIONS:
INCHES (MM)
0.020 (0.51)
0.013 (0.33)
0.050 (1.27)
TYP
45°
0.0098 (0.249)
0.0040 (0.102)
0.010 (0.25)
0.007 (0.18)
0°–8°
0.197 (5.0)
0.189 (4.8)
0.050 (1.27)
0.016 (0.40)
SEATING
PLANE
0.064 (1.63)
0.045 (1.14)
0.244 (6.20)
0.228 (5.79)
8-Pin SOP (M)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents
or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 1998 Micrel Incorporated
MIC5011
12
July 2000
相关型号：
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