BD81870EFV-M Datasheet, PDF (6/36 Pages) Rohm – Step-up / Inverted 2ch Switching Regulator

BD81870EFV-M
12. Output discharge
Inverted DC/DC output capacitor is discharged through DIS1 pin when STB1 is low.
The discharge function can be disabled when STB2=H in SEQON=H mode.
The discharge function can NOT disabled in SEQON=L mode because STB2 controls ON/OFF of Step-up DC/DC.
Step-up DC/DC output capacitor is discharged through DIS2 pin when high-side switch is OFF.
In conditions where HSWON=H, when UVLO of VDD is released, high-side switch is ON.
So, discharge function of step-up DC/DC output capacitor is disabled, even if step-up DC/DC is OFF.
By cutting the route from DIS2 pin to the capacitor, discharge function can be disabled.
OVP function is not disabled because DIS2 pin is used to monitor the output voltage.
In this case, DIS2 pin should be shorted to GND.
13. OVP
By detecting high level of output voltage, this block stops switching and prevent malfunction by over voltage stress.
In inverted DC/DC, when DIS1 pin is -14.5V (typ.) from VDDA level, switching stops.
When DIS1 pin voltage rises, switching starts again. OVP of inverted DC/DC has hysteresis of 1.0V (typ.).
In step-up DC/DC, when VOUT2 in is 20.5V (typ.) from GND level, switching stops.
When VOUT2 pin voltage falls, switching starts again. OVP of step-up DC/DC has hysteresis of 1.5V (typ.).
www.rohm.com
© 2016 ROHM Co., Ltd. All rights reserved.
TSZ22111 • 15 • 001
6/32
TSZ02201-0313AAF00650-1-2
29.July.2016 Rev.001