BD8179MUV

Technical Note

6/12

www.rohm.com

2009.07 - Rev.B

© 2009 ROHM Co., Ltd. All rights reserved.

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Block Function



Step-up Controller

A controller circuit for DC/DC boosting.

The switching duty is controlled so that the feedback voltage FB is set to 1.233 V (typ.).

A soft start operates at the time of starting.



Gate-on Controller

A controller circuit for the positive-side charge pump.

The liner regulator controls so that the feedback voltage FBP will be set to 1.25 V (typ.).



Gate-off Controller

A controller circuit for the negative-side charge pump.

The liner regulator controls so that the feedback voltage FBN will be set to 0.25 V (Typ.).



Gate Shading Controller

A controller circuit for MOS FET Switch

The COM switching synchronize with CTL input.



Start-up Controller

A control circuit for the starting sequence.



REF

A block that generates internal reference voltage. 1.25V (Typ.) is output.



TSD/UVLO/OVP

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

The thermal shutdown circuit is shut down at an IC internal temperature of 175°C and reactivate at 160°C.

The under-voltage lockout protection circuit shuts down the IC when the VIN is 2.4 V (typ.) or below.

The over-voltage lockout protection circuit shuts down the IC when the SUP is 19.0 V (typ.) or over.



OP1～OP5

Operational amplifier block

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Starting sequence

①

②

③

④

①

②

③

④

3.25ms

15ms

2.4

1.25V