tb62217afg TOSHIBA Semiconductor CORPORATION, tb62217afg Datasheet - Page 14

• Manufacturer Part Number: tb62217afg
• Description: Pwm Drive Stepping Motor Driver / Brush Dc Motor Driver Selectable, Dc-dc Converter And Reset Function Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

3.
Function
Note: The RE COMP circuit compares the set current with the output current and generates a signal when the
Current Feedback Circuit and Current Setting Circuit for Motor Driver
The current setting circuit is used to set the reference voltage of the output current using the step current
setting data entered from the serial input pin.
The current feedback circuit is used to deliver a signal to the output control circuit when the output current
reaches the set current. This is done by comparing the reference voltage delivered from the current setting
circuit with the potential difference generated when current flows through the current sense resistor (RRS)
connected between RS and VM.
The chopping waveform generator, to which a capacitor is connected, generates the OSC M (OSC-CLK) as a
chopping frequency reference.
If the Osc_M pin becomes open, the open condition detection function works, thus shutting down the IC. If the
pin is shorted to GND when the IC starts operating, the detection function also works and the IC does not
operate.
V
R
ref
V
S
M
output current reaches the set current.
Current setting circuit
control circuit
Torque
Torque
100%
85%
70%
50%
0.1
Current feedback circuit
V
R
difference
RS
between
S
(detects
voltage
and V
From the
logic unit
circuit 1
M
)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Current
0~3
selector
circuit
current
4-bit
circuit
DA
Step
R
S
circuit
COMP
14
NF (set current reached signal)
Chopping reference generator circuit
waveform generator circuit
Output stop signal (ALL OFF)
Waveform shaper circuit
Chopping reference
OSC_D
DSC Open Short
Detect Unit
TB62217AFG
control unit
2004-11-12
OSCM
Output
Mixed
decay
timing
circuit