MAX17499 Maxim Integrated Products, MAX17499 Datasheet - Page 8

• Manufacturer Part Number: MAX17499
• Description: (MAX17499 / MAX17500) Current-Mode PWM Controllers
• Manufacturer: Maxim Integrated Products

www.DataSheet.co.kr
The MAX17499/MAX17500 current-mode PWM con-
trollers are ideal for isolated and nonisolated power-
supply applications. The devices offer an accurate
input startup voltage programmable through the
UVLO/EN input. This feature prevents the power supply
from entering a brownout condition in case the input
voltage sags below its minimum value. This is important
since switching power supplies increases their input
supply current as the input voltage drops to keep the
output power constant. In addition to this externally
adjustable UVLO feature, the MAX17500 also offers a
bootstrap UVLO with a large hysteresis (11.9V) and
very low startup and operating current, which result in
Current-Mode PWM Controllers with
Programmable Switching Frequency
Figure 1. Nonisolated Power Supply with Programmable Input-Supply Start Voltage
8
PIN
_______________________________________________________________________________________
10
7
8
9
V
SUPPLY
0V
C5
NAME
NDRV
GND
V
IN
CC
R2
R3
Ground Connection
External n-Channel MOSFET Gate Connection
Gate-Drive Supply. Internally generated supply from IN. Decouple V
to GND.
IN Supply. Decouple with a 10nF or larger capacitor to GND. For bootstrapped operation (MAX17500),
connect a startup resistor from the input supply line to IN. Connect the bias winding supply to IN also (see
the Typical Application Circuit). For the MAX17499, connect IN directly to the 9.5V to 24V supply.
Detailed Description
C2
R11
UVLO/EN
COMP
UFLG
CS
FB
1
2
3
4
5
MAX17500
C6
R15
10
9
8
7
6
R12
RT
IN
V
NDRV
GND
CC
an efficient universal input power supply. The switching
frequency of the devices is programmable with an
external resistor.
The MAX17500 is well suited for universal input (recti-
fied 85V AC to 265V AC) or telecom (-36V DC to
-72V DC) power supplies. The MAX17499 is well suited
for low-input-voltage (9.5V DC to 24V DC) power sup-
plies. The devices include an internal clamp at IN to
prevent the input voltage from exceeding the absolute
maximum rating (see Note 2 at the end of the Electrical
Characteristics table). The input is clamped when the
devices are started with a bleed resistor (R1 in Figure 1)
from a high input voltage and the UVLO/EN input is low.
The clamp can safely sink up to 2mA current.
FUNCTION
C2
R1
Pin Description (continued)
C1
D2
CC
Q1
R4
with a 10nF or larger capacitor
T1
D1
C4
R14
R13
V
OUT
Datasheet pdf - http://www.DataSheet4U.net/