The ibrk arrow illustrates this table 1 c4 ctrl4 r4

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Unformatted text preview: ion that must be taken into account when designing an H-bridge circuit. All MOSFETs must be biased to off when the inputs to the circuit are unpredictable (like when the microcontroller is starting up). This will ensure that the MOSFETs on each half-bridge of the H-bridge will never be turned on at the same time. Turning MOSFETs on that are located on the same half-bridge will cause a short across the power supply, ultimately damaging the MOSFETs and rendering the circuit inoperable. Pull-down resistors at each of the MOSFET driver inputs will accomplish this functionality (for the configuration shown in Figure 8). H-BRIDGE MODES OF OPERATION Q1 Q2 Q3 Q4 (CTRL1) (CTRL2) (CTRL3) (CTRL4) Forward on off off on Reverse off on on off Coast off off off off Brake off on off on DS00905B-page 4 2010 Microchip Technology Inc. AN905 SPEED CONTROL The speed of a BDC motor is proportional to the voltage applied to the motor. When using digital control, a pulse-width modulated (PWM) signal is used to generate an average voltage. The motor winding ac...
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