MP6302 – ENERGY STORAGE AND RELEASE CONTROL IC

MP6302 Rev. 1.02

www.MonolithicPower.com

9

7/17/2015

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© 2015 MPS. All Rights Reserved.

APPLICATION INFORMATION

Setting the Storage Voltage

The storage voltage can be set by choosing

appropriate external feedback resistors R1 and

R2 which is shown in Figure 4.

R1

R2

Cstorage

STRG

FB1

Vstorage

Figure 4—Feedback Circuit for Storage

Voltage

The storage voltage can be calculated by:

STORAGE

FB1

R1

V(1

) V

R2

=+

×

For example, if the storage voltage is set to be

8.5V, choose R2 to be 100kΩ, R1 will be then

given by:

100k

(8.5V 1V)

R1

750k

1V

Ω×

−

==

Ω

Table 1 lists the recommended resistors for

different storage voltage settings.

Table 1—Resistor Selection for Different

Storage Voltages

R1 (kΩ)

R2 (kΩ)

8.5

750

100

12

750

68

15

750

53.6

Setting the Release Voltage and Input

Capacitors Selection

The release voltage can be set by external

feedback resistors R3 and R4 shown in Figure

5.

R3

R4

VIN

FB2

Cin

Cf

Figure 5—Feedback Circuit for Realease

Voltage

The release voltage can be calculatedt by:

RELEASE

FB2

R3

V(1

) V

R4

=+

×

The selection of R3 and R4 not only determines

the release voltage, but also impacts the

stability of the release circuit. The 300kΩ-

Table 2 lists the recommended resistors for

different release voltage settings. A 15pF feed-

forward capacitor is recommended for good

release dynamic performance.

Table 2—Resistor and Capacitors Selection

for Different Release Voltages

(V)

R3 (kΩ)R4 (kΩ)

Cf (pF)

11

475

47.5

15

47

10.2

464

49.9

15

47

4.2

324

100

15

47

Storage Capacitor Selection

The storage capacitor is used for energy

storage during normal operation and the energy

will be released to VIN in case of losing input

power. Usually, the small ceramic capacitors or

poscap can be used based on different

applications.

The voltage rating of storage capacitor needs to

be higher than the targeted storage voltage.

The voltage rating of storage capacitor can be

fully utilized since the voltage of storage

capacitor is very stable during normal operation.