8/20

TSZ02201-0S2S0C700240-1-2

© 2020 ROHM Co., Ltd. All rights reserved.

BD68888MUV

14.Sep.2020 Rev.001

www.rohm.com

TSZ22111•15•001

PWM Constant Current Control

1

Current control operation

current is converted voltage due to connect the external resistance to the SENSEx pin, reaches the voltage value set by the

Thereafter the output turned on again after a period of time determined the internal timer. The process repeats itself

constantly.

(Note 1) x = 1, 2, 3 or 4

2

Noise-masking function

In order to avoid misdetection of current detection comparator due to SENSEx spike noise that may occur when the output

(Typ) from the output transistor turned on. This allows constant-current drive without the need for an external filter.

3

Internal Timer

IC internal voltage repeat charging and discharging between VL to VH.

The detection of the internal comparator is masked while charging from VL to VH. This period defines the minimum

ON-time (

the current limit during this period, then the IC enters decay mode. It reaches VL, at which point

the IC internal voltage is

switched back ON. The current output and internal terminal begin charging simultaneously.

Figure 1. Timing Chart of IC Internal Voltage, the SENSEx pin voltage and Output Current

IC Internal Voltage

SENSE Voltage

Output Current

Spike Noise

Current Limit Value

GND

Minimum ON Time

VH

VL

GND

0 mA

Current Limit Value

Chopping Period