M5291P/FP

REJ03D0841-0300 Rev.3.00 Jun 15, 2007

Page 7 of 9

Constant Definition

Constant

Step-down Circuit

Step-up Circuit

Inverse Polarity Circuit

6

ON

6

ON

6

ON

1

1

1

1

− T

OFF

1

− T

OFF

1

− T

OFF

1

+

1

+

1

+

2

• I

OUT (MAX)

2

• I

1

+

(

)

2

• I

1

+

(

)

• T

ON (MAX)

(

)

0.33

0.33

1.17

)

1.17

)

1.17

)

0.33

• T

ON (MAX)

(

)

• T

ON (MAX)

(

)

Note:

Forward Voltage of Diode

Setting switching frequency first and calculate each constant value.

Notes:

1. Peak current sense

In overcurrent function, oscillator is stop, when voltage descend of external detecting resistance is more than 330

mV.

2. ON/OFF Control

If you need stop the action, connected resistance (5 to 10 k

Ω) between supply voltage terminal and timing capacitor

terminal.

3.

is not established more than 0.857, because charge and discharge current ratio fixed 1 : 6.