tb62217afg TOSHIBA Semiconductor CORPORATION, tb62217afg Datasheet - Page 58

• 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

Operating Time of The Motor Over Current Protection Circuit
(ISD dead band time and ISD operating time)
Reference diagram: Timing chart showing over current flowing through a motor
current spikes in switching. The dead band time is in synchronization with the frequency of the OSC for setting
up the chopping frequency (OSC_M).
when the output stops is as follows:
may not work depending on the output control mode and timing.
select a rating that will not cause the maximum power dissipation of the IC to be exceeded and that will not
pose any problem.)
The over current protection circuit has the dead band time to avoid detecting over current accidentally from
The time between the instant when over current starts flowing through the output stage and the instant
Minimum: 4 u fosc_M period
Maximum: 8 u fosc_M period (+ synchronization time  1 fosc_M time)
However, the operating time stated above applies when the over current flows ideally. The over current circuit
Therefore, a protection fuse needs to be inserted in the VM power supply.
(The required rating of the fuse varies depending on the conditions under which the IC is used. Therefore,
When dead band time
Time when over current starts flowing through the output stage (over current state start)
ISD BLANK time
Dead band time
(chopping reference waveform)
fosc_M oscillation
4 u fosc_M period
58
min
ISD operating time
Output stop (RESET state)
(OSC_M)
max
Fosc
TB62217AFG
2004-11-12