MAX829SNTR Просмотр технического описания (PDF) - ON Semiconductor

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производитель

MAX829SNTR

Switched Capacitor Voltage Converters

ON Semiconductor 

MAX828 MAX829

+ Rout

Rout OF SINGLE DEVICE

NUMBER OF DEVICES

Vin+

3

2

C1

+

4

MAX828

MAX829

“1”

5

1

3

C1

+

4

5

MAX828

MAX829

“n”

...

2

Vout

1

Diode Protection for Heavy Loads

When heavy loads require the OUT pin to sink large

currents being delivered by a positive source, diode

protection may be needed. The OUT pin should not be

allowed to be pulled above ground. This is accomplished by

connecting a Schottky diode (1N5817) as shown in Figure

7.

GND

4

MAX828

MAX829

Vout = Vin–

C2

+

Figure 5. Paralleling MAX828s or MAX829s to

Reduce Output Resistance

Voltage Doubler/Inverter

Another common application of the MAX828/829 is

shown in Figure 6. This circuit performs two functions in

combination. C1 and C2 form the standard inverter circuit

described above. C3 and C4 plus the two diodes form the

voltage doubler circuit. C1 and C3 are the pump capacitors

and C2 and C4 are the reservoir capacitors. Because both

sub–circuits rely on the same switches if either output is

loaded, both will droop toward GND. Make sure that the

total current drawn from both the outputs does not total more

than 40mA.

Vin+

3

2

C1

+

4

MAX828

MAX829

D1, D2 = 1N4148

D1

OUT

1

Figure 7. High V– Load Current

Layout Considerations

As with any switching power supply circuit good layout

practice is recommended. Mount components as close

together as possible to minimize stray inductance and

capacitance. Also use a large ground plane to minimize

noise leakage into other circuitry.

5

1

Vout = Vin–

C2

+

D2

Vout = (2Vin) –

+

C3

+ C4 (VFD1) – (VFD2)

Figure 6. Combined Doubler and Inverter

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5

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