MAX5022EVKIT Maxim Integrated Products, MAX5022EVKIT Datasheet - Page 6

• Manufacturer Part Number: MAX5022EVKIT
• Description: EVAL KIT FOR MAX5022
• Manufacturer: Maxim Integrated Products

Specifications of MAX5022EVKIT

• Main Purpose: AC/DC, Primary Side
• Outputs And Type: 1, Isolated
• Power - Output: 5W
• Voltage - Output: 5V
• Current - Output: 1A
• Voltage - Input: 85 ~ 265VAC
• Regulator Topology: Flyback
• Frequency - Switching: 262kHz
• Board Type: Fully Populated
• Utilized Ic / Part: MAX5022
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

NDRV did not switch enough times to build up sufficient
voltage across the tertiary output to power the device.
The device will go back into UVLO and will not start. Use
a low-leakage ceramic or film capacitor for C2 and C3.
As a rule of thumb, off-line power supplies keep typical
startup times to less than 500ms even in low-line condi-
tions (85VAC input). Size the startup resistor, R
ply the maximum startup bias of the IC (85µA) plus the
additional current required for charging the capacitors
C2 and C3 in less than 500ms. This resistor dissipates
continuous power in normal operation, despite the fact
that it is only used during the startup sequence.
Therefore it must be chosen to provide enough current
for the low-line condition as well as have an appropriate
power rating for the high-line condition (265VAC). In
most cases, split the value into two resistors connected
in series for the required voltage of approximately
400VDC.
The typical value for C2 and C3 is 220nF. The startup
resistor, R
rent of 85µA and the charging current for C2 and C3.
Bypass capacitor C3 charges to 9.5V and C2 charges
Current-Mode PWM Controllers for Isolated
Power Supplies
Figure 1. Universal 5W Off-Line Standby Power Supply
6
265VAC IN
85VAC TO
_______________________________________________________________________________________
N
G
L
S
, provides both the maximum quiescent cur-
CENTRAL SEMICONDUCTOR
CENTRAL SEMICONDUCTOR
CBR1-D100S
FAIRCHILD
CNY17-3
240k
AC
AC
OPTO
R9
0.22 F
10 F
400V
C1
C3
250mA, 75V
CMPD914
D1
470
1.2k
L2
R8
V
OPTO
H
CC
MAX5022
GND
U1
C9
10 F
400V
S
NDRV
8200pF
, to sup-
V
CS
IN
C8
R1
360k
R2
360k
R
C2
0.22 F
S
= R1 + R2
10
R6
R11
10
D1
to 24V all within the desired time period of 500ms, for
an overall average charging current of 15µA. Hence,
the startup resistor must provide a total of at least
100µA. Developing 100µA from an input voltage of
480 H, 60T
Figure 2. V
N1
INTERNATIONAL RECTIFIER
IRFRC20
25
20
15
10
R
1.78
1%
5
0
CS
0
8T
CTX03-15256
1000pF
T1
C7
NOTE: ALL RESISTORS ARE 5% UNLESS OTHERWISE SPECIFIED.
IN
ON SEMICONDUCTOR
3T
and V
MBRS340T3
3A, 40V
50
D2
150 F
CC
6.3V
INSTRUMENTS
C4
TLV431AIDBV
During Startup
V
V
CC
IN
OPTO
TEXAS
1k
TIME (ms)
1%
R3
100
IC COMES OUT OF UVLO
(WAKEUP)
V
WINDING (NORMAL OPERATION)
V
FULLY CHARGED
IN
CC
V
NDRV BEGINS SWITCHING
0.01 F
SUPPLIED BY TERTIARY
CC
10
R10
BYPASS CAPACITOR
DROPS SLIGHTLY WHEN
C5
8.06k
24.9k
V
1%
1%
R5
IN
R4
SUPPLIED BY C2
150
0.1 F
C6
+5V OUT
200