8.2.3 Application Curves

The following scope captures show how the output duty cycle changes to as VCC increases. This allows the motor to spin at a constant speed as VCC changes. At VCC = 3.9 V, the output duty cycle is 100% on. As the VCC voltage increases to greater than 4 V, the output duty cycle begins to decrease. The output duty cycle is shown at VCC = 4.5 V, VCC = 5 V and VCC = 5.5 V.

• Channel 1 – OUT1: IN1 – Logic Low
• Channel 2 – OUT2: IN2 – Logic High
• Channel 4 – Motor current: VSET – 1 V
• Motor used: NMB Technologies Corporation, PPN7PA12C1

Figure 10. Output Pulse Width Modulating at VCC = 3.9 V

Figure 12. Output Pulse Width Modulating at VCC = 4.5 V

Figure 14. Output Pulse Width Modulating at VCC = 5.5 V

Figure 11. Output Pulse Width Modulating at VCC = 4 V

Figure 13. Output Pulse Width Modulating at VCC = 5 V