.

Control circuit

The control circuit for each CONT pin is configured as shown below. When a voltage more than a given value is applied,

the level on the pin is fixed by clamp diode D1.

Description

.

.

= 1/2

× V13 + 0.6 (0.3) + 0.6

where 0.9 V is for pin 9.

1.2 V is for pins 6, 15.

= 1/2

× V13 + (0.9 or 1.2)

.

The maximum voltage at which the CONT pin is brought to GND level is fixed by the level at which the Q2 is completely

turned OFF.

This level is:

1/2

× V13 – V

Switching is performed at a level less than this.

.

To turn ON/OFF

When turning ON:

.

Operation finish voltage

Pins 6, 15 : = 1/2

× V13

Pin 9 :

= 1/2

× V13 + V

BE

= 1/2

× V13 + 0.6 [V]

.

R

The minimum value of resistor R is fixed by this equation.

Example

Therefore, R = 100 k

Ω presents no problem.

When turning OFF:

Bring the level on the CONT pin to a level less than:

1/2

× V13 – V

Unit (resistance:

Ω, capacitance: F)

Control pin

Current route

at clamp mode

Note: For D1, a Schottky diode is used for pin 9

and a silicon diode is used for pins 6, 15.

To turn ON the control circuit to finish the

LA3246

No.2651-7/13