Vdd, 10mA PWM, Variable Frequency and Duty Cycle - (Low Side Drive

Vdd, 10mA PWM, Variable Frequency and Duty Cycle - (Low Side Drive)

 

Functional Description

Driver Properties

Driver Specifications

Interface Schematic

 

Functional Description

This output is a PWM (pulse width modulated) signal with a configured duty cycle and variable frequency controlled by the design logic. 

 

The PWM frequency is variable from 50% to 200% of a configured base frequency.  The “percentage” value is provided by the design logic.  The PWM frequency at the output pin is equal to the BaseFrequency*PercentageValue/100.  (Example: BaseFrequency = 1000Hz, PercentageValue = 150, PWM frequency = 1500 Hz)

This output is a low side switch, which depending on the configuration, can source Vdd and from 10mA.

 

Hardware Interface: The PSoC pin drives the output directly or through a high voltage and current rated MOSFET. An optional diode protects the MOSFET when used with inductive loads. 

 

Software Interface: The PWM frequency and duty cycle are controlled by one 16 bit unsigned value.  The control values for the frequency and duty cycle must be combined into one 16-bit value.

 

The high order byte controls the output frequency of the PWM.  The PWM frequency is controlled with a value between 50 and 200.  This value is the percentage of the configured base frequency that will yield the desired PWM output frequency.  (Example: 50 results in a generated PWM frequency of 0.50*BaseFrequency, 200 results in a generated PWM frequency of 2.0*BaseFrequency) 

 

The low order byte controls the duty cycle of the PWM.  The PWM duty cycle is controlled with a value between 0 and 100.  This value is the duty cycle percentage in 1% increments (Example: 45 results in 45%).

 

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Driver Properties

User Configurable Properties

 

·        BaseFrequency: this is the output frequency of the PWM when the associated percentage value is equal to 100.  The output frequency of the PWM is calculated using this property and the percentage value determined by the driver transfer function. 

 

Non-Configurable Properties

 

·        VA Mode: Vdd 10mA Low Side

·        Polarity: Negative

 

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Driver Specifications

·        Voltage: Vdd (max)

·        Current: 10mA (max)

 

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Interface Schematic

 

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