UCS1002-2 datasheet(40/114 Pages) MICROCHIP

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Programmable USB Port Power Controller with Charger Emulation

Datasheet

Revision 1.4 (07-16-13)

SMSC UCS1002

DATASHEET

5.1.2

Sleep State Operation

When the UCS1002 is in the Sleep state, the device will be in its lowest power state. The high-speed

switch, bypass switch, and the port power switch will be disabled. The Attach and Removal Detection

feature will be disabled. VBUS will be near ground potential. The ALERT# pin will not be asserted. If

asserted prior to entering the Sleep state, the ALERT# pin will be released. The A_DET# pin will be

released.SMBus activity is limited to single byte read or write.

The first data byte read from the UCS1002 when it is in the Sleep state will wake it; however, the data

to be read will return all 0’s and should be considered invalid. This is a “dummy” read byte meant to

wake the UCS1002. Subsequent read or write bytes will be accepted normally. After the dummy read,

the UCS1002 will be in a higher power state (see Figure 5.6). After communication has not occurred

for tIDLE_SLEEP, the UCS will return to Sleep.

Figure 5.5 shows timing diagrams for waking the UCS1002 via external pins. Figure 5.6 shows the

timing for waking the UCS1002 via SMBus.

Figure 5.5 Wake Timing via External Pins

M1 or M2

Port power switch closed

(Active state)

tPIN_WAKE

Wake with M1 or M2 to Active State Data Pass-through Mode

(PWR_EN enabled, S0 = ‘0’, EM_EN = ‘0’, VS > VS_UVLO)

Bypass switch closed

(Detect state)

tPIN_WAKE

Wake with S0

(VS > VS_UVLO, M1 & M2 & EM_EN not all ‘0’ and not set to Data Pass-through)

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