Technical Note

9/21

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2010.12 - Rev.A

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BD8163EFV

●

Block Function

・

Step-up Controller

A controller circuit for DC/DC boosting.

The switching duty is controlled so that the feedback voltage FB1 is set to 1.24 V (typ.). A soft start operates at the time of

starting. Therefore, the switching duty is controlled by the SS pin voltage.

・

Charge Pump Control 1

A controller circuit for the positive-side charge pump.

The switching amplitude is controlled so that the feedback voltage FB2 will be set to 1.24 V (typ.). The start delay time can

be set in the DLS terminal at the time of starting. When the DLS voltage reaches 0.6 V (Typ.), switching waves will be

output from the C1L and C2L pins.

・

Charge Pump Control 2

A controller circuit for the negative-side charge pump.

The switching amplitude is controlled so that the feedback voltage FB2 will be set to 0.6 V (Typ.).

・

Gate Shading Controller

A controller circuit of gate shading.

The Vo2GS and GSOUT are in on/off control according to IG pin input.

・

Regulator Control

A regulator controller circuit for VDD voltage generation.

・

DET 1 to DET 4

A detection circuit of each output voltage. This detected signal is used for the starting sequential circuit.

・

Start-up Controller

A control circuit for the starting sequence.

・

VREF

A block that generates internal reference voltage. 1.24V (Typ.) is output.

・

TSD/UVLO

Thermal shutdown/Under-voltage lockout protection/circuit blocks.

The thermal shutdown circuit is shut down at an IC internal temperature of 175℃ and reset at 160℃. The under-voltage

lockout protection circuit shuts down the IC when the VCC is 1.8 V (typ.) or below.

・

Starting sequence

For malfunction prevention, starting logic control operates so that each output will rise in order of

As shown below, detectors DET1 to DET3 detect that the output on the detection side has reached 90% (typ.) of the set

voltage, and starts the next block.

Starting sequence model

Fig. 26 Starting Timing Chart

VDD

Reg

DET1

CTL1

Step up

Vo1

DET2

CTL2

Negative

Charge

Pump

Vo3

DET3

CTL3

Positive

Charge

Pump

Vo2

VCC

DET4

CLT4

5V

2.5V

Vcc

VDD

Vo2

Vo1

Vo3

0

0

0