MAX610 MAXIM [Maxim Integrated Products], MAX610 Datasheet - Page 6

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

has been at 5V for a delay period determined by the
value of a capacitor connected between V- and RD. This
makes the OUV output well suited for driving the reset
input of microprocessors.
Upon power-up, the MAX611 OUV output will stay low
until the output has been at 5V for the length of the delay
period (Figure 9). This provides a reliable power-up reset
to the microprocessor. Whenever the MAX611 output
falls below 4.65V (as during a brownout), the OUV pin will
go low, resetting the microprocessor. The output voltage
must remain above 4.65V for the entire delay period
before the OUV pin will go high: each time the voltage
falls below 4.65V the reset delay period is restarted.
The delay period is approximately 30 milliseconds for
each 0.01µF of capacitance. Leave pin 4 floating if this
additional delay is not desired.
In some circuits, a voltage higher than 5V is needed to
drive relays, triacs, or power MOSFET gates. The DC
output voltage at V+ is +12V (+18V for MAX612) and
can be used to trigger triacs as shown in Figure 11.
The V+ voltage is equal to the MAX610/MAX611 zener
voltage until the load current (total current drawn from
the +12V and the +5V) approaches the maximum avail-
able output current (40mA for each µF of C1 capaci-
tance with 110VAC 60Hz input, 70mA/µF with 220VAC
50Hz input). The ripple on the +12V is relatively low.
With the components shown in Figure 10 the ripple volt-
age is about 5mVp-p at 10mA load current and 20mV
at 40mA load current.
AC-to-DC Regulator
(110/220VAC to 5.0VDC)
Figure 7. Adjustable Output Voltage
6
117VAC
_______________________________________________________________________________________
V
1/2W
OUT
47
R1*
= 1.3
(
1 +
0.5 F
1M
C1*
R2
R3
+12V Output for Driving Triacs,
)
7
1
AC1
AC2
V-
2
MAX610
Relays, and MOSFETs
V
SENSE
V
V+
V
OUV
OUT
SET
8
6
5
4
3
+1.3V TO
R2
R3
V
+9V
OUT
+12V
Figure 11 shows a simple way to combine a MAX610
with a battery to form an uninterruptible 5V power sup-
ply. When the 110VAC line voltage is present, resistor
R2 trickle charges the 7.2V NiCd battery. When the
110VAC is removed, the NiCd battery will supply cur-
rent through diode D1, and the MAX610 output will
remain a constant 5V. The MAX610 will continue to
deliver 5V out until V+ is approximately 5.8V and the
battery voltage is approximately 6.5V. Alkaline 9V or
NiCd 8.4V batteries are also suitable; R2 should not be
used with the non-rechargeable 9V alkaline battery. If
isolation from the power line is required, drive AC1 and
AC2 with a transformer as shown in Figure 6.
Figure 8. Short-Circuit Current Limiting
Figure 9a. Power-Up Reset Delay
117VAC
117VAC
t
(in sec)
DELAY
1/2W
47
1/2W
47
R1
R1
= C3 x C3
(in F)
150V
150V
2 F
Uninterruptible 5V Power Supply
1.5 F
1M
C1
1M
C1
RMS
RMS
7
1
7
1
AC1
N.C.
AC1
AC2
V-
V
SET
2
4
MAX611
MAX610
V-
2
16VDC
47 F
V
SENSE
V
V
V+
OUV
SENSE
V
OUT
V+
OUV
RD
OUT
8
8
C2
6
5
3
4
6
5
3
R
SENSE
I
CL
=
C3
R
0.6V
SENSE
+5V
TO P
RESET