st1115c Silicon Touch Technology Inc., st1115c Datasheet - Page 5

• Manufacturer Part Number: st1115c
• Description: Speed Control Double Coil Brushless Motor Driver
• Manufacturer: Silicon Touch Technology Inc.

HIN Input and the Output Driver States
Internal PWM Duty Cycle v.s. VT Input
The relation of VT v.s. Duty Cycle is shown below, which illustrates a linear relation within the
range of 3.18~3.88 V (V
is biased in this linear region through a thermistor-resistor divider. In this way, the fan speed
can vary linearly with respect to the temperature variation; the higher temperature results in
the faster speed. Additionally, applying the exterior PWM command to the VT terminal can
also control the fan speed. Note that the low level and high level of the exterior PWM
command must be lower than 3.18 V and higher than 7.7 V (V
exterior PWM is active low.
SP-ST1115CD-A.005
Different voltage levels of the VT pin correspond to different internal PWM duty cycles.
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
100%
50%
HIN
0%
H
L
DD
= 12 V). If the linear temperature control is desired, the VT terminal
PWM Duty Ratio v.s. VT voltage
3.18
Voltage of VT ( VDD=12 Volt)
OFF
Version
ON
O1
3.88
：
A.005
7.7
OFF
ON
O2
DD
12 Volt
= 12 V), respectively. The
ST1115C/ST1115D
Page
：
4