MIC2010 Datasheet, PDF (1/9 Pages) Micrel Semiconductor – USB Power Controller Advance Information

MIC2010
MIC2010/MIC2070
USB Power Controller
Advance Information
Micrel
General Description
The MIC2010 is a dual channel USB power switch designed
to support the power distribution requirements for USB Wakeup
from the ACPI S3 state. The MIC2010 will directly switch its
two outputs between a 5V main supply and a 5V auxiliary
supply normally provided in ATX style power supplies.
The MIC2010 will adjust its current-limit threshold according
to the ACPI state it is in. In the normal active ACPI 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 a value
determined by an external resistor to minimize the current
that is supplied by the auxiliary supply, thereby ensuring that
voltage regulation is maintained even during fault conditions.
The MIC2010 provides make-before-break switching to en-
sure 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 MIC2070 option latches the output off upon detecting an
overcurrent condition lasting for more than 5ms minimum.
The output can be reset by either toggling the EN inputs of the
MIC2070-1/-2 or by removing the load. Latching the output
off provides a circuit breaker mode of operation which re-
duces power consumption during fault conditions.
Features
• Compliant to USB power distribution specifications
• 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
• Circuit breaker options with auto-reset (MIC2070)
• Undervoltage lockout
Applications
• Desktop PCs
• Notebook PCs
• Notebook docking stations
• LAN Servers
• PC motherboard
Typical Application
ATX Power Supply
5V MAIN
5V STANDBY
ON/OFF 1
ON/OFF 2
S3# CONTROL
82801AA or Equivalent
SLP S3#
SLP S5#
OC0
OC1
Overcurrent Port 1
Overcurrent Port 1
MIC2010-1P/-2P
MAIN
AUX OUT1
EN1
OUT2
EN2
S3# RSET1
FAULT1
FAULT1 RSET2
GND
100µF
100µF
V_BUS
D+
D–
GND
V_BUS
D+
D–
GND
Figure 1. USB Wakeup From ACPI S3 System Diagram
Downstream
USB
Port 1
Downstream
USB
Port 2
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
September 2000
1
MIC2010/2070