Ricoh RH5RH12B Manual Do Utilizador

V

OUT

=5.0V

Unless otherwise provided, V

IN

=3V, Vss=0V, I

OUT

=10mA, Topt=25˚C, and use External Circuit of Typical

Application (FIG. 1).

(Note 1)   Soft-Start Circuit is operated in the following sequence :

(1)  V

IN

is applied.

(2)  The voltage (Vref) of the reference voltage unit is maintained at 0V for about 200µs after the application of V

IN

.

(3)  The output of Error Amp. is raised to “H” level during the maintenance of the voltage (Vref) of the reference voltage unit.

(4)  After the rise of Vref, the output of Internal Error Amp. is gradually decreased to an appropriate value by the function of Internal Phase

Compensation Circuit, and the Output Voltage is gradually increased in accordance with the gradual decrease of the output of Internal Error

Amp.

(Note 2)   I

LX

is gradually increased after Lx Switch is turned ON.  In accordance with the increase of I

LX

, V

LX

is also increased.  When V

LX

reaches V

LX

lim

,

Lx Switch is turned OFF by an Lx Switch Protection Circuit.

V

OUT

Output Voltage

V

IN

Input Voltage

Vstart

Start-up Voltage

Vhold

Hold-on Voltage

I

DD

1

Supply Current 1

I

DD

2

Supply Current 2

I

LX

Lx Switching Current

I

LX

leak

Lx Leakage Current

fosc

Oscillator Frequency

Maxdty

Oscillator Maximum Duty

Cycle

η

Efficiency

t

start

Soft-Start Time

V

LX

lim

V

LX

Voltage Limit

4.875

5.000

5.125

V

8

V

Iout=1mA,Vin:0

→

2V

0.8

0.9

V

Iout=1mA,Vin:2

→

0V

0.7

V

To be measured at OUT Pin

(excluding Switching Current)

30

45

µA

To be measured at OUT Pin

(excluding Switching Current)

2

5

µA

V

IN

=5.5V

V

LX

=0.4V

80

mA

V

LX

=6V,V

IN

=5.5V

0.5

µA

40

50

60

kHz

on (V

LX

“L” ) side

70

80

90

%

70

85

%

Time required for the rising

0.5

2.0

ms

Note1

of V

OUT

up to 5V.

Lx Switch ON

0.65

0.8

1.0

V

Note2