MAX610 MAXIM [Maxim Integrated Products], MAX610 Datasheet - Page 8

• Manufacturer Part Number: MAX610
• Description: AC-to-DC Regulator(110/220VAC to 5.0VDC)
• Manufacturer: MAXIM [Maxim Integrated Products]

AC-to-DC Regulator
(110/220VAC to 5.0VDC)
The component values shown in the Typical Applications
section are suitable for most applications. The following
section gives the reasons for the particular component val-
ues chosen, explains the effect of using other values, and
discusses the component specifications.
The current-limiting capacitor (C1) is the most critical com-
ponent for a 110/220VAC input power supply based on
the MAX610 family. It must continuously withstand the full
line voltage, so it should be rated for AC operation. A con-
servative designer will use a capacitor rated for at least
150V
280V
must be a non-polarized type such as polyester (Mylar™)
or polypropylene metallized film. Metallized film capaci-
tors are preferred over metal foil capacitors, since metal
foil capacitors are more likely to fail as a short circuit.
The value of C1 determines both the power dissipation of
the MAX610/MAX611/MAX612 and the maximum avail-
able output current. The value of C1 should be the small-
est value that will deliver the desired output current at
minimum line voltage, since the power dissipated by the
MAX610/MAX611/MAX612 increases with increasing val-
ues of C1. Table 1 gives the formula for calculating C1 as
a function of the desired output current. Table 2 shows
some typical component suppliers and part numbers.
Figure 11. Uninterruptible 5V Power Supply
8
______________Component Selection
117VAC
60Hz
_______________________________________________________________________________________
RMS
RMS
1/2W
47
R1
working voltage for 110VAC circuits, and at least
for 220VAC or 240VAC circuits. This capacitor
175V
1 F
C1
1M
RMS
Current-Limiting Capacitor, C1
7
1
4
V
AC1
AC2
SET
V-
2
MAX610
47 F
16V
C2
V
SENSE
V
V+
OUV
OUT
8
1N4001
6
5
3
UNINTER-
RUPTIBLE
+5V DC
OUTPUT
7.2V
NiCd
BATTERY
R2
1.8k
The current-limiting resistor (R1) limits the maximum
peak current that occurs when power is first applied to
the MAX610 just as the power line voltage is at its maxi-
mum. The instantaneous peak current must be limited
to 5A. For 110VAC, input voltage R1 must be 33Ω or
greater; for 220VAC, input voltage R1 must be 68Ω or
greater. The recommended values are 47Ω for
110VAC and 100Ω for 220VAC. The power dissipation
in R1 is constant, independent of the load current.
Figure 12. Polarity Insensitive Battery-Powered Supply
Figure 13. Simple Battery Charger
BATTERY
117VAC
60Hz
1/2W
47
150V
1.5 F
1M
RMS
7
1
AC1
AC2
7
1
V
Current-Limiting Resistor, R1
SET
4
AC1
AC2
MAX612
V-
2
MAX610
V-
2
10 F
25V
V
V
SENSE
V
V+
SENSE
OUV
V
V+
OUT
V
8
OUT
SET
8
C2
100 F
16V
6
5
3
6
5
4
2.4k
10k
R2
+6.7V
R3
+5V
V
V
OUT
BATTERY
=
6V
GEL CELL
BATTERY
- 0.6V