USB5537B datasheet(22/79 Pages) MICROCHIP

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USB5537B

DS00001682C-page 22

 2012 - 2015 Microchip Technology Inc.

4.4.2

POLY-FUSE

An alternate method of downstream power control is to utilize poly-fuse devices. In this configuration, the poly-fuse

devices are used to report overcurrent conditions to the USB5537B through the OCS input, as shown in Figure 4-13.

4.5

Charging Port Configurations

The device can also be configured to operate as a charging port for one or more downstream ports. Ganged port power

control and/or overcurrent is not supported if any of the downstream ports are configured as charging ports. If a port is

configured to support a charging port mode, either a standard port power controller or a UCS1002 may be implemented.

For more information on charging port support, refer to Section 5.1, "Charging Port Configuration," on page 24.

4.5.1

PORT POWER CONTROLLER

The only special limitation of using the device as a charging port is that the port power controller must be capable of the

higher current to support the charging port modes. Refer to Section 4.4.1, "Port Power Controller," on page 20 for more

information on this implementation.

4.5.2

UCS1002

Using a UCS1002 device as a downstream port power controller is only supported on ports that are enabled as charging

ports.

If the UCS1002 is implemented, the USB5537B communicates with all of the implemented UCS1002 ports over SMBus

using one of the PRT_CTLx/OCSx signals as the SMCLK/SMDAT. Additionally, DYNCPDIS_N becomes the UCS_SM-

BALERT_N signal. Multiple UCS1002 devices may be connected to the SMBus in parallel.

After reset, for any enabled charging ports, the USB5537B performs SMBus commands on the configured

PRT_CTLx/OCSx signals and checks UCS1002 devices at specific addresses (see Table 4-1) to confirm which ports

are utilizing UCS1002 devices as the downstream power controllers.

FIGURE 4-13:

POLY-FUSE IMPLEMENTATION

OCS

USB

Device

Poly Fuse

USB553x

10k

3.3V

USB5537B Datenblatt(PDF) 22 Page - Microchip Technology