L6258EXTR STMicroelectronics, L6258EXTR Datasheet - Page 22

• Manufacturer Part Number: L6258EXTR
• Description: IC MOTOR DRVR UNIV PWM PWRSO-36
• Manufacturer: STMicroelectronics
• Type: Driverr

Specifications of L6258EXTR

• Applications: DC Motor Driver, Stepper Motor Driver
• Number Of Outputs: 2/1
• Current - Output: 1.5A
• Voltage - Load: 12 V ~ 40 V
• Voltage - Supply: 4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: PowerSO-36 Exposed Bottom Pad
• Operating Supply Voltage: 12 V to 40 V
• Mounting Style: SMD/SMT
• Operating Temperature: 150 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Operating Temperature: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PWM current control loop
3.5
22/32
Figure 9.
We can see that the effect of the load pole is cancelled by the zero of the Bx block ; the total
Aloop cross a the 0dB axis with a slope of -20dB/decade, having in this way a stable system
with an high gain at low frequency and a bandwidth of around 8KHz.
To increase the bandwidth of the system, we should increase the gain of the Bx block,
keeping the zero in the same position. In this way the result is a shift of the total Aloop
transfer function up to a greater value.
Effect of the Bemf on the current control loop stability
In order to evaluate what is the effect of the Bemf voltage of the stepper motor we have to
look at the load block:
Aloop bode plot (compensated)
L6258EX