LA3246 查看數據表（PDF） - SANYO -> Panasonic
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LA3246 Datasheet PDF : 13 Pages
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LA3246
. 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.
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.
Unit (resistance: Ω, capacitance: F)
Description
. Switching level VSW of the control circuit is fixed by voltage V13 which is 1/2 of the voltage on pin 13.
VSW = 1/2 V13
. Clamp voltage VCLP at the time a voltage is applied to the CONT pin
VCLP = 1/2 × V13 + VD1 + VBE1
= 1/2 × V13 + 0.6 (0.3) + 0.6
where 0.9 V is for pin 9.
= 1/2 × V13 + (0.9 or 1.2)
1.2 V is for pins 6, 15.
. 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 – VBE2 = 1/2 × V13 – 0.6 [V]
Switching is performed at a level less than this.
. To turn ON/OFF
When turning ON:
To turn ON the control circuit to finish the
operation, IB is required. Control voltage
VOUT is obtained with IB of 4 µA min.
. VCONT min = R × IB max + Operation finish voltage.
IB = 4 µA
Operation finish voltage
Pins 6, 15 : = 1/2 × V13
Pin 9 : = 1/2 × V13 + VBE
. = 1/2 × V13 + 0.6 [V]
VCONT max = R × IB max + Clamp voltage
R is restricted by IB max.
When the supply voltage is fixed, clamp voltage VCLP is fixed. When resistor R is fixed based on a balance with capacitor C,
resistor R is restricted by VCONT max. as shown below.
IB max = 100 µA ^ VCONT max – VCLP
R
The minimum value of resistor R is fixed by this equation.
Example
Assuming VCC = 10 V, VCONT max = 10 V, Rmin is 50 kΩ.
Therefore, R = 100 kΩ presents no problem.
When turning OFF:
Bring the level on the CONT pin to a level less than:
1/2 × V13 – VBE2 = 1/2 × V13 – 0.6 [V]
No.2651-7/13
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