isp1160 NXP Semiconductors, isp1160 Datasheet - Page 33

• Manufacturer Part Number: isp1160
• Description: Isp1160 Embedded Universal Serial Bus Host Controller
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 13963
Product data
Fig 26. Using an internal OC detection circuit.
’n’ represents the downstream port number (n = 1 or 2).
V OC = 5 V
V BUS
9.8.1 Using an internal OC detection circuit
V BUS
downstream
connector
5 V
USB
port
The internal OC detection circuit can be used only when V
a 5 V power supply. The HCD must set AnalogOCEnable, bit 10 of the
HcHardwareConfiguration register, to logic 1.
An application using the internal OC detection circuit and internal 15 k pull-down
resistors is shown in
AnalogOCEnable and DownstreamPort15Kresistorsel to logic 1. They are bit 10 and
bit 12 of the HcHardwareConfiguration register, respectively.
When H_OCn_N detects an overcurrent status on a downstream port, H_PSWn_N
will output HIGH, a logic 1 to turn off the 5 V power supply to the downstream port
V
on the 5 V power supply to the downstream port V
In general applications, a P-channel MOSFET can be used as the power switch for
V
the drain, and H_PSWn_N to the gate. Call the voltage drop across the drain and
source, the overcurrent detection voltage (V
circuit, a voltage comparator has been designed-in, with a nominal voltage threshold
( V
logic 1 to turn off the P-channel MOSFET. If the P-channel MOSFET has a R
150 m , the overcurrent threshold will be 500 mA. The selection of a P-channel
MOSFET with a different R
BUS
BUS
trip
. When there is no such detection, H_PSWn_N will output LOW, a logic 0 to turn
. Connect the 5 V power supply to the source of the P-channel MOSFET, V
) of 75 mV. When V
P-Channel
MOSFET
47 pF
Rev. 05 — 24 December 2004
(2 )
H_PSWn_N
22
22
H_OCn_N
Figure
V CC
H_DMn
H_DPn
OC
DSon
26. In this example, the HCD must set both
exceeds V
will result in a different overcurrent threshold.
OC detect
regulator
15 k
trip
(2 )
bit 12
, H_PSWn_N will output a HIGH level,
OC
Configuration
). For the internal overcurrent detection
HcHardware
ATX
OC select
1
0 Reg
BUS
PSW
C/L
Embedded USB Host Controller
.
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
HC CORE
ISP1160
CC
SIE
Configuration
HcHardware
(pin 56) is connected to
bit 10
ISP1160
004aaa066
DSon
33 of 88
BUS
of
to