Micrel MIC2012ZM Usb power controller Datasheet

MIC2012
Micrel
MIC2012/MIC2072
USB Power Controller
General Description
Features
The MIC2012 is a dual channel USB power switch designed to
support the power distribution requirements for USB Wakeup
from the ACPI S3 state. The MIC2012 will directly switch its
two outputs between a 5V main supply and a 5V auxiliary
supply normally provided in ATX style power supplies.
The MIC2012 will adjust its current-limit threshold according
to the ACPI state it is in. In the normal active S0 state the current-limit is set at 500mA minimum per channel satisfying the
USB continuous output current specification. In the S3 state
the current-limit can be reduced to only 100mA per channel
to minimize the current that is supplied by the auxiliary supply
thereby ensuring that voltage regulation is maintained even
during fault conditions.
The MIC2012 provides make-before-break switching to ensure
glitch-free transitions between the S3 and S0 states. Each
channel is also thermally isolated from the other so that a
fault in one channel does not effect the other. FAULT status
output signals are also provided indicating overcurrent and
thermal shutdown conditions.
The MIC2072 option latches the output off upon detecting
an overcurrent condition for more than 5ms minimum. The
output can be reset by either toggling the EN inputs of the
MIC2072-1, -2 or by removing the load. Latching the output
off provides a circuit breaker mode of operation which reduces
power consumption during fault conditions.
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Compliant to USB power distribution specifications
UL Recognized Component
Two completely independent switches
Integrated switching matrix supports ACPI S0/S3 state
transitions without external FET circuits
Make-before-break switching ensures glitch-free
transitions
No back-feed of auxiliary supply onto main supply during standby mode
Bi-level current-limit preserves auxiliary supply voltage
regulation in standby mode
Thermally isolated channels
Thermal shutdown protection
Fault status outputs with filter prevents false assertions
during hot-plug events
Latched thermal shutdown options with auto-reset
(MIC2072)
Undervoltage lockout
Applications
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Desktop PCs
Notebook PCs
Notebook Docking stations
LAN Servers
PC Motherboards
Typical Application
ATX Power Supply
5V MAIN
VBUS
5V STANDBY
D+
MIC2012P
MAIN
AUX
S3 Control
D–
OUT1
OUT2
Downstream
USB
Port 1
GND
100F
S3#
FAULT1#
VBUS
D+
FAULT2#
GND
100F
82801AA or Equivalent
D–
Downstream
USB
Port 2
GND
SLP S3#
SLP S5#
OC0
OC1
Overcurrent Port 1
Overcurrent Port 1
Figure 1. USB Wakeup with Control Input
UL Recognized Component
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
January 2005
1
MIC2012/2072
MIC2012
Micrel
Ordering Information
Part Number
Enable
Fault Output
Circuit Breaker
Range
Temperature
Range
Package
Standard
Pb-Free
MIC2012BM(1)
MIC2012YM(1)
n/a
Open-Drain
0°C to +70°C
8-lead SOIC
MIC2012CM
MIC2012ZM
n/a
Open-Drain
0°C to +70°C
8-lead SOIC
MIC2012PCM
MIC2012PZM
MIC2012-1PCQS
MIC2012-1PZQS
n/a
Internal Pull-Up
0°C to +70°C
8-lead SOIC
Active High
Internal Pull-Up
0°C to +70°C
16-lead QSOP
MIC2012-2PCQS
MIC2012-2PZQS
Active Low
Internal Pull-Up
MIC2072-1PCQS
MIC2072-2PZQS
Active High
Internal Pull-Up
Δ
0°C to +70°C
16-lead QSOP
0°C to +70°C
16-lead QSOP
MIC2072-2PCQS
MIC2072-2PZQS
Active Low
Internal Pull-Up
Δ
0°C to +70°C
16-lead QSOP
Note:
1.
Contact factory for availablity
Pin Configuration
FAULT1
FAULT1
1
8 FAULT2
S3# 2
7 OUT1
AUX 3
6 MAIN
GND 4
5 OUT2
8-Pin SOIC (M)
1
16 FAULT2
EN1 2
15 EN2
S3# 3
14 OUT1
NC 4
13 OUT1
AUX 5
12 MAIN
NC 6
11 MAIN
NC 7
10 OUT2
GND 8
9 OUT2
16-Pin QSOP (QS)
MIC2012/2072
2
January 2005
MIC2012
Micrel
Pin Description
Pin Number
(MIC2012)
Pin Number
(MIC2012-1, -2)
Pin Name
1
1
FAULT1
Fault Status (Output): Internal pull-up or open-drain. Asserted LOW when
Channel is in a thermal shutdown state or overcurrent condition for more
than 5ms. MIC2072 latches this output in its asserted state upon an overcurrent condition. Toggling EN1 or removing the load will reset the circuit
breaker latch and deassert FAULT1.
n/a
2
EN1
Enable (Input): Channel 1, active-high (–1) or active-low (–2). Toggling this
input also resets the latched output of the MIC2072.
2
3
S3#
Control (Input): When this input is HIGH, the MAIN inputs are connected to
OUT1 and OUT2 via 100mΩ MOSFET switches. When this input is LOW
the AUX inputs are connected to OUT1 and OUT2 via 500mΩ MOSFET
switches.
3
5
AUX
Auxiliary 5V Supply (Input): Also used as power supply for internal circuitry.
n/a
4, 6, 7
NC
4
8
GND
Ground
5
9, 10
OUT2
Channel 2 (Output): For MIC2012-1, -2 both pins must be externally connected together.
6
11, 12
MAIN
5V Main Supply (Input): All MAIN inputs must be connected together externally.
7
13, 14
OUT1
Channel 1 (Output): For MIC2012-1, -2 both pins must be externally connected together.
n/a
15
EN2
Enable (Input): Channel 2, active-high (–1) or active-low (–2). Toggling this
input also resets the latched output of the MIC2072.
8
16
FAULT2
Fault Status (Output): Internal pull-up or open-drain. Asserted LOW when
Channel 2 is in a thermal shutdown state or overcurrent condition for more
than 5ms. MIC2072 latches this output in its asserted state upon an overcurrent condition. Toggling EN2 or removing the load will reset the circuit
breaker latch and deassert FAULT2.
January 2005
Pin Function
No Connection: This pin may be connected to other pins without restriction.
3
MIC2012/2072
MIC2012
Micrel
Absolute Maximum Ratings (Note 1, Note 4)
Operating Ratings (Note 2)
Supply Voltage (VIN, VMAIN, VAUX) .....................–0.3V to 6V
EN1, EN2, S3# Input Pins .................................–0.3V to 6V
FAULT#, OUT1, OUT2 Output Pins...................–0.3V to 6V
FAULT Output Current ................................................ 25mA
ESD Rating, Note 3 ...................................................... 2kV
Supply Voltage (VMAIN, VAUX) ...................... +4.5V to +5.5V
Ambient Temperature (TA) ............................ –0°C to +70°C
Junction Temperature (TJ) ........................ Internally Limited
Package Thermal Resistance
QSOP (θJA)....................................................................... 163°C/W
SOIC (θJA)......................................................................... 160°C/W
Electrical Characteristics
VMAIN = 5V; AUX = 5V; TA = 25°C; unless noted
Symbol
Parameter
Condition
VMAIN
MAIN Supply Voltage
IMAIN (ON)
MAIN Supply Current Switches On
Note 5
IMAIN (OFF)
MAIN Supply Current Switches Off
S3# = 1, no load
Note 5, (MIC20x2-1, MIC20x2-2 only)
ILEAK
MAIN Reverse Leakage Current,
VAUX
AUX Supply Voltage
IAUX ON
AUX Supply Current,
both switches on, Note 5
No load
S3# = 0
IAUX OFF
AUX Supply Current, switches
off. (MIC20x2-1, MIC20x2-2 only)
No load
S3# = 0
VUV/AUX
AUX Undervoltage Lockout
Threshold
VAUX increasing
VAUX decreasing
VHYS
AUX Undervoltage Lockout
Hysteresis
Min
Typ
Max
4.5
5.0
5.5
V
16
22
µA
5
µA
+10
µA
5.0
5.5
V
0.6
1
mA
5
µA
4.0
3.8
V
V
S3# = 1, no load
S3# = 0, both switches ON, VMAIN = 0V
–10
4.5
3.1
2.9
200
Units
mV
RDSMAIN
MAIN On-Resistance, Each Output
S3# = 1, IOUT = 500mA
100
140
mΩ
RDSAUX
AUX On-Resistance, Each Output
S3# = 0, IOUT = 100mA
500
700
mΩ
ILIMIT(MAIN)
MAIN Current-Limit Threshold
S3# = 1, VOUT = 4.0V, ramped load
0.8
2.0
A
MAIN Short-Circuit Current-Limit
VOUT = 0V
0.65
1.8
A
AUXCurrent-Limit Threshold
S3# = 0, VOUT = 4.0V, ramped load
105
195
mA
AUX Short-Circuit Current-Limit
VOUT = 0V, COUT = 100µF
S3#, EN1, EN2. Input
Threshold Voltage
(EN1, EN2, for MIC20x2-x only)
Low-to-High transition
ILIMIT(AUX)
VTH
High-to-Low transition
150
80
0.8
mA
1.5
1.7
V
2.0
V
VHYS
EN1, EN2 and S3# Input Hysteresis
(EN1, EN2, for MIC20x2-x only)
IIN
S3#, EN1, EN2 Input Current
(EN1, EN2, for MIC20x2-x only)
VS3/EN = 5V, 0V
–1
1
µA
IOFF
OUT1, OUT2 Leakage Current
(MIC2012-x, MIC2072-x only)
Outputs are off, VOUT = 0
–10
10
µA
Pull-Up Current During Latched
Output State (MIC2072-1, -2)
Outputs latched off
MIC2012/2072
200
4
1
mV
mA
January 2005
MIC2012
Micrel
Symbol
Parameter
Condition
Min
VTH LATCH
Latch Reset Threshold
(MIC2072, MIC2072-x only)
VOUT Rising
Minimum Output Slew Rate
to Reset Latch
(MIC2072, MIC2072-x only), Note 6
Overtemperature Threshold
TJ increasing, single channel
TJ decreasing, single channel
TJ increasing, both channels
TJ decreasing, both channels
VOL
FAULT Output Low Voltage
IFAULT = 5mA
VOH
FAULT Output High Voltage
(MIC2012-1P,-2P),(MIC2072-1P,-2P)
IFAULT = –20µA
FAULT Output Off Current
(Not Applicable to 'P' Options)
VFAULT = 5V
Typ
Max
Units
1.95
V
0.4
V/s
140
120
160
150
°C
°C
°C
°C
0.2
4
V
V
0.2
10
µA
TH
MAIN to S3# Hold Time, Note 6
Figure 5
5
ms
TS
MAIN to S3# Set-up Time, Note 6
Figure 5
0
ms
tDLY
FAULT Delay Filter Response Time
(Overcurrent only), Note 7
Output shorted to ground, Figure 4
5
tOC
Overcurrent Response Time
Output shorted to ground, Figure 4
MAIN output
AUX output
10
20
ms
2
2
µs
µs
tON(MAIN)
MAIN Output Turn-On Time
RL = 10Ω, CL = 1µF, Figure 3
2
ms
tOFF(MAIN)
MAIN Output Turn-Off Time
(MIC20x2-x only)
RL = 10Ω, CL = 1µF, Figure 3
35
µs
tr(MAIN)
MAIN Output Rise Time
RL = 10Ω, CL = 1µF, Figure 3
2
ms
tf(MAIN)
MAIN Output Fall Time
(MIC20x2-x only)
RL = 10Ω, CL = 1µF, Figure 3
32
µs
tON(AUX)
AUX Output Turn-On Time
RL = 50Ω, CL = 1µF, Figure 3
0.6
ms
tOFF(AUX)
AUX Output Turn-Off Time
(MIC20x2-x only)
RL = 50Ω, CL = 1µF, Figure 3
120
µs
tr(AUX)
AUX Output Rise Time
RL = 50Ω, CL = 1µF, Figure 3
0.5
ms
tf(AUX)
AUX Output Fall Time
(MIC20x2-x only)
RL = 50Ω, CL = 1µF, Figure 3
115
µs
tXMA
MAIN to AUX
Cross Conduction Time, Note 8
S3# transition to 0
5
7.5
ms
tXAM
AUX to MAIN
Cross Conduction Time, Note 8
S3# transition to 1
5
7.5
ms
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 4.
All voltages are referenced to ground.
Note 5.
For MIC20x2-1(P) OFF occurs when VEN < 0.8V and ON occurs when VEN > 2.4V. For MIC20x2-2(P) OFF occurs when VEN > 2.4V and ON
occurs when VEN < 0.8V.
Note 6.
Guaranteed by design. Not production tested.
Note 7.
Assumes only one channel in current-limit. Delay circuitry is shared among channels so it is possible for tDLY to be 40ms max if one channel
enters current-limit as the other is about to time-out.
Note 8.
Cross conduction time is the duration in which both MAIN and AUX internal switches are on subsequent to S3# transitioning.
January 2005
5
MIC2012/2072
MIC2012
Micrel
Timing Diagrams
50%
VE N
tO F F
tON
90%
VOUT
10%
Figure 2. MIC2012/72-1
50%
VE N
tO F F
tON
90%
VOUT
10%
Figure 3. MIC2012/72-2
Output shorted to ground
VOUT
IOUT
ILIMIT
tOC
FAULT#
tDLY
Figure 4. Overcurrent Response Timing
tH
tS
MAIN
S3#
1.5V
1.5V
Figure 5. MAIN to S3# Timing
MIC2012/2072
6
January 2005
MIC2012
Micrel
Test Circuit
VOUT
Device
Under OUT
Test
IOUT
RL
CL
tr
tf
90%
VOUT
10%
10%
January 2005
90%
7
MIC2012/2072
MIC2012
Micrel
Typical Characteristics
Main Supply Current
vs. Temperature
Main Supply Current
vs. Temperature
(Main 1 and Main 2 = ON)
V MAIN = 4.5, 5.0, 5.5V
EN1 = EN2 = [ON],V
25
AUX
= S3# = 5.0V
0.25
0.225
15
5.0 V MAIN
4.5 V MAIN
10
5
0.05
IOUT = 0µA
0 20 40 60
TEMPERATURE (°C)
80 100
Main Short-Circuit
Current-Limit Threshold
vs. Temperature
1.40
1.35
V MAIN = 5.0V
= S3# = 4.5, 5.0, 5.5V
V
EN1 = EN2 = [OFF],V
5.0V AUX
4.5V AUX
5.5V AUX
0.025
0
-40 -20
IOUT = 0µA
0 20 40 60
TEMPERATURE (°C)
80 100
0 20 40 60
TEMPERATURE (°C)
80 100
1.05
4.5V AUX
1.00
-40 -20
Main Rise-Time
vs. Temperature
2000
(AUX 1 and AUX 2 = ON)
V AUX = S3# = 4.5, 5.0, 5.5V
4.5V AUX
V AUX = 4.5, 5.0, 5.5V
900 V
= S3# = 0V
MAIN
800
600
1000
500
800
400
5.5 V AUX
R L = 10Ω
C L = 1µF
200
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
100
-40 -20
Enable Threshold (decreasing)
vs. Temperature
(MIC2012-1/-2)
5.5V AUX
2.0
1.8
1.6
80 100
Enable Threshold (increasing)
vs. Temperature
(MIC2012-1/-2)
2.2
5.5V AUX
1.4
4.5 V AUX
1.4
1.2
-40 -20
0 20 40 60
TEMPERATURE (°C)
5.0 V AUX
80 100
5.0V MAIN
1.0
-40 -20
Enable Threshold (decreasing)
vs. Temperature
( MIC2012-1/-2)
1.8
5.5V MAIN
4.5 V AUX
1.2
V AUX = 4.5, 5.0, 5.5V
V MAIN = S3# = 5.0V
80 100
(Output Latched Off–MIC2072)
1600
4.5V MAIN
0 20 40 60
TEMPERATURE (°C)
Pull-Up Current
vs. Temperature
1800
2.0
2.0
V AUX = 4.5, 5.0, 5.5V
V MAIN = S3# = 5.0V
1.6
5.0 V AUX
4.5 V AUX
80 100
2.0
1.8
4.5V MAIN
0 20 40 60
TEMPERATURE (°C)
(MIC2012-1/-2)
2.2
0.20
5.0 V AUX
0.10
0.00
-40 -20 0 20 40 60
TEMPERATURE (°C)
IOUT = 0µA
EN1 = EN2 = [ON]
200
V AUX = 4.5, 5.0, 5.5V
5.5V AUX
5.0 V AUX
4.5 V AUX
300
Enable Threshold (increasing)
vs. Temperature
I OUT = 0µA
EN1 = EN2 = [OFF]
5.5V AUX
700
5.0 V AUX
(AUX 1 and AUX 2 = OFF)
V MAIN = S3# = 0V
80 100
1000
V MAIN = 5.0V
AUX Supply Current
vs. Temperature
0.50
0.40
0.30
0 20 40 60
TEMPERATURE (°C)
AUX Supply Current
vs. Temperature
(EN Toggled)
400
1.10
-40 -20
5.0V AUX
4.5 V MAIN
600
1.15
1.20
1.10
1200
1.20
AUX
1.25
1.15
1400
5.5V AUX
1.25
1.8
5.0 V MAIN
1600
1.30
1.00
0.90
0.80
0.70
0.60
= S3# = 5.0V
AUX
5.5V MAIN
1800
AUX
V MAIN = 5.0V
= S3# = 4.5, 5.0, 5.5V
V
V MAIN = 4.5, 5.0, 5.5V
0.15
0.125
0.1
0.075
0
-40 -20
1.30
0.2
0.175
5.5V MAIN
20
Main Short-Circuit Current-Limit
vs. Temperature
(Main 1 and Main 2 = OFF)
30
V MAIN = 5.0 V
V AUX = S3# = 4.5, 5.0, 5.5V
1400
1.6
5.5V AUX
1200
5.0V MAIN
1000
1.6
1.4
1.4 V MAIN = 4.5V to 5.5V
V AUX = S3# = 5.0V
1.2
1.2
-40 -20
MIC2012/2072
0 20 40 60
TEMPERATURE (°C)
80 100
800
5.5V MAIN
600
V MAIN = 4.5V to 5.5V
V AUX = S3# = 5.0V
1.0
-40 -20
0 20 40 60
TEMPERATURE (°C)
8
5.0V AUX
4.5V AUX
400
80 100
200
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
January 2005
MIC2012
Micrel
Output Reset Threshold
vs. Temperature
3.00
2.75
(Output Latched Off –MIC2072)
V OUT Rising
V
V
2.50
MAIN
AUX
= 5.0 V
= S3# = 4.5, 5.0, 5.5V
5.5V AUX
2.25
2.00
1.75
1.50
-40 -20
January 2005
4.5V AUX
5.0V AUX
0 20 40 60
TEMPERATURE (°C)
80 100
9
MIC2012/2072
MIC2012
Micrel
Functional Characteristics
VOUT FAULT VAUX
(2V/div) (2V/div) (2V/div)
AUX Shutdown by UVLO
IOUT
(50mA/div)
VAUX ramps from 0V to 5V
V
VMAIN = S3#
= V= 0V = 5V
ENMAIN
= [ON] AUX
RLOAD = 50CL = 100F
CLOAD = 1F
RL = 10
VMAIN = VAUX = 5V
CL = 100F
RL = 10
Main Start-up by UVLO
Main Shut-down by UVLO
IOUT
VOUT FAULT VMAIN
(200mA/div) (2V/div) (2V/div) (2V/div)
2.96V
S3# = 5V
EN = [ON]
RLOAD = 10½
CLOAD = 1µF
VMAIN = VAUX;VMAIN & VAUX ramp from 5V to 0V
TIME (500s/div)
TIME (10ms/div)
Main Turn-On Response
Main Turn-Off Response
FAULT EN
(5V/div) (5V/div)
VOUT
(5V/div)
VOUT
(2V/div)
VMAIN = VAUX =5V
S3# = 5V
EN toggles from [OFF] to [ON]
RLOAD = 10
CLOAD = 1F
IOUT
(200mA/div)
IOUT
(200mA/div)
VAUX ramps from 5V to 0V
VMAIN = S3# = 0V
EN = [ON]
RLOAD = 50
CLOAD = 1F
TIME (10ms/div)
VMAIN = VAUX;VMAIN & VAUX ramp from 0V to 5V
S3# = 5V
EN = [ON]
RLOAD = 10
3.20V
CLOAD = 1F
TIME (250s/div)
MIC2012/2072
2.96V
TIME (500s/div)
FAULT
EN
(5V/div) (5V/div)
IOUT
VOUT FAULT VMAIN
(200mA/div) (2V/div)(2V/div) (2V/div)
IOUT
VOUT FAULT VAUX
(50mA/div) (2V/div) (2V/div) (2V/div)
AUX Start-up by UVLO
VMAIN = VAUX =5V
S3# = 5V
EN toggles from [ON] to [OFF]
RLOAD = 10
CLOAD = 1F
TIME (100s/div)
10
January 2005
MIC2012
Micrel
FAULT
EN
(5V/div) (5V/div)
AUX Turn-Off Response
IOUT
(50mA/div)
VAUX =5V
VMAIN = S3# = 0V
EN toggles from [OFF] to [ON]
RLOAD = 50
CLOAD = 1F
IOUT
(50mA/div)
VAUX =5V
VMAIN = S3# = 0V
EN toggles from [ON] to [OFF]
RLOAD = 50
CLOAD = 1F
VOUT
(5V/div)
VOUT FAULT EN
(5V/div) (5V/div) (5V/div)
AUX Turn-On Response
TIME (100s/div)
Turn-On from S3# to AUX
Turn-Off from AUX to S3#
VOUT
(2V/div)
FAULT
S3#
(5V/div) (5V/div)
VOUT FAULT S3#
(5V/div) (5V/div) (5V/div)
TIME (100s/div)
IOUT
(50mA/div)
IOUT
(50mA/div)
VAUX =5V, VMAIN = 0V
EN = [ON]
S3# toggles from [HI] to [LOW]
RLOAD = 50
CLOAD = 1F
VAUX =5V, VMAIN = 0V
S3# toggles from [LO] to [HI]
EN = [ON]
RLOAD = 50
CLOAD = 1F
TIME (1ms/div)
Main Inrush Current into CLOAD
Main-Ramped to Short by MOSFET
FAULT
(5V/div)
VOUT FAULT EN
(5V/div) (5V/div) (5V/div)
TIME (100s/div)
VOUT
(2V/div)
VMAIN = VAUX = 5V
S3# = 5V
EN toggles from [OFF] to [ON]
RLOAD = OPEN
CLOAD = 10F, 100F, 560F
1.4A
IOUT
(500mA/div)
IOUT
(500mA/div)
CL = 560F
CL = 100F
CL = 10F
TIME (500s/div)
January 2005
VMAIN = VAUX =5V
S3# = 5V, EN = [ON]
CLOAD = 1F
RLOAD toggles from > 1k to <0.5
TIME (50ms/div)
11
MIC2012/2072
MIC2012
Micrel
Main Turn-On into Short
VOUT
FAULT
EN
(5V/div) (5V/div) (5V/div)
FAULT
(5V/div)
AUX Ramped to Short by MOSFET
VOUT
(2V/div)
VAUX = 5V
VMAIN = S3# = 0V, EN = [ON]
RLOAD toggles from >1k to <0.5
CLOAD = 1F
VMAIN = VAUX =5V
S3# = 5V
EN toggles from [OFF] to [ON]
RLOAD = Short
CLOAD = 1F
TIME (25ms/div)
TIME (2.5ms/div)
AUX Turn-On into Short
AUX Inrush Current into Large CLOAD
VOUT FAULT
EN
(5V/div) (10V/div) (5V/div)
VOUT FAULT EN
(2V/div) (5V/div) (5V/div)
IIN
(500mA/div)
IOUT
(100mA/div)
1.2A
230mA
VAUX =5V
VMAIN = S3#= 0V
EN toggles from [OFF] to [ON]
ILOAD < 10mA
CLOAD = 220F
IIN
(50mA/div)
IOUT
(100mA/div)
VAUX =5V
VMAIN = S3# = 0V
EN toggles from [OFF] to [ON]
CLOAD = 100F
AUX Inrush Current into Small CLOAD
Main-to-AUX Cross Conduction
S3#
VOUT
(5V/div) (5V/div)
TIME (2.5ms/div)
VAUX =5V
VMAIN = S3# = 0V
EN toggles from [OFF] to [ON]
ILOAD < 10mA
CLOAD = 10F
IAUX
(50mA/div)
IMAIN
(50mA/div)
TIME (250s/div)
TIME (100s/div)
MIC2012/2072
VMAIN = VAUX = 5V
S3# toggles from [HI] to [LO]
EN = [ON]
RLOAD = 50
950s
C
= 1F
LOAD
IIN
(50mA/div)
VOUT FAULT
EN
(5V/div) (10V/div) (5V/div)
TIME (2.5ms/div)
12
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MIC2012
Micrel
VMAIN = VAUX =5V
S3# toggles from [LO] to [HI]
EN = [ON]
RLOAD = 50
CLOAD = 1F
3.96ms
IMAIN
(50mA/div)
IAUX
(50mA/div)
VOUT
(5V/div)
S3#
(5V/div)
AUX-to-Main Cross Conduction
TIME (1ms/div)
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MIC2012/2072
MIC2012
Micrel
Functional Diagram
MAIN
Current
Limit
MAIN
FET
Charge Pump
+
Gate Control
EN
OUT
AUX
FET
AUX
S3#
Current
Limit
Thermal
Sense
AUX
* 'P' options only
Latch
10ms
Timer
*
/FAULT
*MIC2070-1/2 Only
To Other Channel
Functional Description
The MIC2012/2072 are designed to support the power distribution requirements for USB wakeup from the ACPI S3 state.
It integrates two independent channels under control of input
S3#. When S3# is asserted LOW (S3 state) the MIC2012/2072
will switch a 500mΩ, 100mA MOSFET switch from the AUX
input to each of its two outputs. Conversely when the S3#
input is HIGH (S0 state) the MIC2012/72 will switch a 100mΩ,
500mA MOSFET switch from the MAIN input to each of its
two outputs. The lower current limit during the ACPI S3 state
helps to ensure that the standby supply maintains regulation
even during fault conditions.
Thermal Shutdown
Thermal shutdown is employed to protect the device from
damage should the die temperature exceed safe margins
due mainly to short circuit faults. Thermal shutdown shuts off
the output MOSFET and asserts the FAULT output if the die
temperature reaches 140°C and the overheated channel is
in current limit. The other channel is not affected. If, however,
the die temperature exceeds 160°C, both channels will be
shut off even if neither channel is in current limit.
Power Dissipation
The device’s junction temperature depends on several factors such as the load, PCB layout, ambient temperature and
package type. The power dissipated in each channel is
PD = RDS(on) × IOUT2 where RDS(on) is the on-resistance of
the internal MOSFETs and IOUT is the continuous output
current.
Total power dissipation of the device will be the summation of
PD for both channels. To relate this to junction temperature,
the following equation can be used:
MIC2012/2072
14
TJ = PD × θJA + TA
where:
TJ = junction temperature
TA = ambient temperature
θJA = is the thermal resistance of the package
Current Sensing and Limiting
The current-limit thresholds are preset internally for each
state. The preset level prevents damage to the device and
external load but still allows a minimum current of 100mA or
500mA to be delivered to the load depending on the state of
the device according to the S3# input. When S3# is LOW the
current-limit is set at 100mA minimum. When S3# is HIGH
the current-limit is set at 500mA minimum.
Should an over-current condition last longer than tDLY, the
MIC2072 will latch the faulty output off. The output will remain
off until either the load is removed or the EN signal (MIC20721, -2) is toggled. When the MIC2072 enters a latched output
condition a 1mA pull-up current source is activated. This
provides a way to automatically reset the output once the
load is removed without the need to toggle the enable input
such as in the MIC2072. Please refer to Figure 7 for timing
details.
The MIC2012 will automatically reset its output when the
die temperature cools down to 120°C. The MIC2012 output
and FAULT signal will continue to cycle on and off until the
device is disabled or the fault is removed. Figure 6 depicts
typical timing. Depending on PCB layout, package, ambient
temperature, etc., it may take several hundred milliseconds
from the incidence of the fault to the output MOSFET being
shut off. This time duration will be shortest in the case of a
January 2005
MIC2012
Micrel
dead short on the output.
exceeds the current-limit threshold. The FAULT response
delay time tDLY is typically 10ms.
Fault Status Output
The FAULT signal is an active-low output with an open-drain
or weak pull-up configuration. FAULT is asserted (active-low)
when either an overcurrent or thermal shutdown condition
occurs. In the case of an overcurrent condition, FAULT will
be asserted only after the flag response delay time, tDLY, has
elapsed. This ensures that FAULT is asserted only upon valid
overcurrent conditions and that erroneous error reporting is
eliminated. For example, false overcurrent conditions can
occur during hot-plug events when a highly capacitive load
is connected and causes a high transient inrush current that
Undervoltage Lockout
Undervoltage lockout (UVLO) prevents the output MOSFET
from turning on until the AUX input exceeds approximately
3.5V. UVLO ensures that the output MOSFETs remain off
to prevent high transient inrush current due to stray or bulk
load capacitance. This helps to ensure that the power supply
Overcurrent Fault
EN
(MIC2010-2)
VOUT
FAULT
Thermal Shutdown
Reached
Figure 6. MIC2012 System Timing
Overcurrent Fault
EN
(MIC2070-2)
VOUT
FAULT
Load Removed–
Output Reset
Figure 7. MIC2072 System Timing—
Output Resets When Load is Removed
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MIC2012/2072
MIC2012
Micrel
Package Information
16-Pin QSOP (QS)
8-Pin SOIC (M)
MICREL INC.
2180 FORTUNE DRIVE
SAN JOSE, CA 95131
USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com
This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's
use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2004 Micrel Incorporated
MIC2012/2072
16
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