Rainbow Electronics MAX5074 - Manual (Page 8)

MAX5074
Detailed Description
The MAX5074 PWM power IC is the primary-side
controller for voltage-mode, isolated forward or flyback
power converters. This device provides a high degree of
integration aimed at reducing the cost and printed circuit
board area of isolated output power supplies. Use the
MAX5074 primarily in 48V power bus applications.
The MAX5074 is a complete power IC capable of deliver-
ing up to 15W of output power. This device contains PWM
circuitry and integrated power MOSFETs. Figure 1 shows
the MAX5074’s block diagram. The MAX5074 includes
undervoltage lockout, overtemperature shutdown, and
short-circuit protection for enhanced performance and
reliability. Operation up to 500kHz allows the use of small
external magnetics and capacitors.
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
8 _______________________________________________________________________________________
OVT
UVLO
REFOK
REGOK
OVRLD
T
T
5V
5V
80 µA
33 µA
IFLT
5V
OVRLD
CPWM
ILIM
CUVLO
1
4
REGOUT
RCFF
3
5
6
FLTINT
RAMP
OPTO
7
9
CSS
GND
20
19
18
8
17
INBIAS
HVIN
UVLO
PPWM
BST
15 XFRMRH
14 DRVIN
13 XFRMRL
16 DRNH
12 SRC
11 PGND
2 RTCT
10 CS
REGOK
REG
OVT
REFOK
REF
(1.25V)
7.5V
50 Ω
GND
Q
D
R
Q
R
T-FF
SHDN
OSC
50 Ω
GND
R
S
Q
CLK
THERMAL
SHUTDOWN
OVT
1.25V
UVLO
80ns
DELAY
LEADING-
EDGE
DELAY
ONE
SHOT
LEVEL
SHIFT
10MHz
PGND
150mV
QH
QB
QL
0.4 Ω
30 Ω
0.4 Ω
MAX5074
2.7V/1.9V
Figure 1. Block Diagram