TPS23750
TPS23770
www.ti.com
SLVS590A – JULY 2005 – REVISED AUGUST 2005
INTEGRATED 100-V IEEE 802.3af PD AND DC/DC CONTROLLER
FEATURES
•
Complete 802.3af PoE Interface
– Features derived from the TPS2375
– 100 V, 0.6
Ω
Internal Pass MOSFET
– Standard and Legacy UVLO Choices
– Fixed 140 mA Inrush Limit
Primary Side DC/DC Converter Control
– Minimum External Component Count
– Current Mode Control
– Isolated and Non-Isolated Topologies
– Programmable Operating Frequency
– Current Sense Leading-edge Blanking
– 50% Duty Cycle Limiting
– Voltage Output Error Amplifier
Internal PoE and Converter Sequencing
Industry-Standard 20 Lead Package
Industrial Temperature Range: –40°C to 85°C
DESCRIPTION
The TPS23750 integrates the functionality of the
TPS2375 with a primary-side dc/dc PWM controller.
The designer can create a front-end solution for
PoE-PD applications with minimum external
components. The TPS23770 is identical to the
TPS23750 with the exception of the undervoltage
lockout turn-on voltage, which is compatible with
legacy systems.
The PoE front end has all the necessary IEEE
802.3af functions including detection, classification,
undervoltage lockout and inrush control. The PoE
input switch is integrated within the TPS23750.
The dc/dc controller section is designed to support
flyback, forward, and nonsynchronous low-side switch
buck topologies.
The external switching MOSFET and current sense
resistor provide flexibility in topology, power level, and
current limit. The full-featured dc/dc controller in-
cludes programmable soft start, hiccup type fault
limiting, 50% maximum duty cycle, programmable
constant switching frequency, and a true volt-
age-output error amplifier. Additional protection fea-
tures provide for robust designs.
•
•
•
•
•
APPLICATIONS
All PoE PD Devices Including:
– Wireless Access Points
– VoIP Phones
– Security Cameras
From Ethernet
Transformers
V
DD
R
DET
SENP
DET
0.1
m
F
58V
From Spare
Pairs or
Transformers
R
CLASS
CLASS
Low Voltage
Isolated
Output
V
SS
COMP
BL
T PS23750
V
BIAS
MODE
V
BIAS
FREQ
TMR
V
DD
AUX
V
BIAS
GATE
RSP
COM
RTN
RSN
C
BIAS
C
TMR
SEN
FB
TLV431
Figure 1. Typical Application
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005, Texas Instruments Incorporated
TI [ TEXAS INSTRUMENTS ]
