UCS1001 datasheet(30/59 Pages) MICROCHIP

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USB Port Power Controller with Charger Emulation

Datasheet

Revision 1.2 (05-21-12)

SMSC UCS1001

DATASHEET

There is one non-recommended configuration which places the UCS1001 in the Detect state, but

VBUS will not be discharged and a portable device attachment will not be detected. For the

recommended configurations, see Table 4.1, "Power States Control Settings".



NOT RECOMMENDED: PWR_EN is enabled, S0 = ‘1’, and M1, M2, and EM_EN are all ‘0’.

There are two methods for transitioning from the Detect state to the Active state: automatic and host-

controlled.

4.1.3.1

Automatic Transition from Detect to Active

For the Detect state, set S0 to ‘1’, enable PWR_EN, set the EM_EN, M1, and M2 controls to the

desired Active mode (Table 8.1, "Active Mode Selection"), and supply VS > VS_UVLO. When a portable

device is attached and an Attach Detection event occurs, the UCS1001 will automatically transition to

the Active state and operate according to the selected Active mode.

4.1.3.2

Host-Controlled Transition from Detect to Active

For the Detect state, set S0 to ‘1’, set the EM_EN, M1, and M2 controls to the desired Active mode

(Table 8.1, "Active Mode Selection"), and configure one of the following: 1) disable PWR_EN and

supply VS, or 2) enable PWR_EN and don’t supply VS. When a portable device is attached and an

Attach Detection event occurs, the host must respond to transition to the Active state. Depending on

the control settings in the Detect state, this could entail 1) enabling PWR_EN or 2) supplying VS above

the threshold.

APPLICATION NOTE: If S0 is '1', PWR_EN is enabled, and VS is not present, the A_DET# pin will cycle if the

current draw exceeds the current capacity of the bypass switch.

4.1.3.3

State Change from Detect to Active

When conditions cause the UCS1001 to transition from the Detect state to the Active state, the

following occurs:

1. The Attach Detection feature will be disabled; the Removal Detection feature remains enabled,

unless S0 is changed to ’0’.

2. The bypass switch will be turned off.

3. The discharge switch will be turned on briefly.

4. The port power switch will be turned on.

4.1.4

Active State Operation

Every time that the UCS1001 enters the Active state and the port power switch is closed, it will enter

the mode as instructed by the host controller (see Chapter 8, Active State). The UCS1001 cannot be

in the Active state (and therefore, the port power switch cannot be turned on) if any of the following

conditions exist:

1. VS < VS_UVLO.

2. PWR_EN is disabled.

3. M1, M2, and EM_EN are all set to '0'.

4. S0 is set to ‘1’ and an Attach Detection event has not occurred.

UCS1001 Datasheet(PDF) 30 Page - Microchip Technology

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