January 2005

1

M9999-101104

MIC2010/2070

Micrel

MIC2010/MIC2070

USB Power Controller

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

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 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

reduces power consumption during fault conditions.

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

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

• UL File #179633

Applications

• Desktop PCs

• Notebook PCs

• Notebook docking stations

• LAN Servers

• PC motherboard

Typical Application

MIC2010-1P/-2P

D+

D–

GND

MAIN

AUX

OUT1

EN1

EN2

Downstream

USB

Port 1

100µF

5V MAIN

ATX Power Supply

S3#

FAULT1

FAULT1

D+

D–

GND

Downstream

USB

Port 2

OUT2

RSET1

RSET2

GND

5V STANDBY

82801AA or Equivalent

SLP S3#

SLP S5#

OC0

OC1

Overcurrent Port 1

Overcurrent Port 1

ON/OFF 1

ON/OFF 2

100µF

S3# CONTROL

Figure 1. USB Wakeup From ACPI S3 System Diagram

UL Recognized Component