FlexCase

Digital Output Guide

Prerequisites

  • Complete the quick start guide for a tutorial on connecting to the FlexCase and flashing binaries

FlexCase S & FlexBench 1.3 Or Higher

Summary of DO (Digital Output)

A summary of the outputs is provided below.

Features Low Side Output High Side Output
Operating Voltage Range 0 – 36 V 5 – 36 V
Maximum Load Voltage 40 V 41 V
ON-State Resistance 160 mΩ 90 mΩ (per channel)
Recommended Load Current 3 A 3 A
Short Circuit Detection 7 A 25 A (Combined Channels)
Diagnostic Functions NA NA
Recommended Switching DO: On/off
PWM: 0-20 kHz (10%-90% duty cycle)		 DO: On/off
PWM: 0-12 kHz (10%-90% duty cycle)
Status Feedback NA NA
Load Types Recommended Resistive, inductive Resistive, inductive, capacitive

LSO:

  • LSO_IN Input Signal (Set DO/PWM): This is an active high digital signal that can be set either HIGH or LOW.
  • LSO_EN (Low Side Digital Output Enable): When set to HIGH, the switch is enabled, allowing the LSO1_IN signal to control the output effectively.

HSO:

  • HSO_IN (Set DO/PWM): This is an active high digital signal that can be driven either HIGH or LOW.

Info on Protection

Protection Features Low Side Output High Side Output
Overcurrent Protection ✅ ✅
Overtemperature Protection ✅ ✅
Overvoltage Protection ✅ ✅
Undervoltage Protection ✅ ✅
Reverse Battery Protection ❌ ✅
ESD Protection ✅ ✅
Short Circuit Protection ❌ ✅
Open Load Detection ❌ ✅
Load Dump Protection ❌ ✅
Maximum Load Inductance Specification ✅ ✅

LSO:

  • Overvoltage Clamping: This feature limits the drain-source voltage and manages power dissipation effectively.
  • Thermal Protection: The chip includes an integrated temperature sensor that shuts the device down during overtemperature conditions.
  • Overcurrent Limitation: This function handles short circuits or excessive currents, automatically shutting down the device if overtemperature is detected. Once the temperature reaches back to normal operating state, the chip is automatically reset to normal mode.

HSO:

  • Loss of Ground Protection: In the event of a loss of ground, the device automatically turns off or remains off to protect itself.
  • Undervoltage Protection: The device turns off when the supply voltage drops below a certain threshold and turns back on when voltage is restored, with protection functions becoming active.
  • Overvoltage Protection: This is managed by an integrated clamp mechanism, which limits the current through a ground resistor.
  • Reverse Polarity Protection: The device uses resistors to limit current through the logic and sense transistors. However, no protection functions are active during reverse polarity.
  • Overload Protection: This includes current limitation to maintain safe power levels and temperature sensors to prevent overheating. The device will switch off when necessary until it is manually reset via the input pin.

FlexCase S & FlexBench 1.2 Or Lower

Summary of DO (Digital Output)

A summary of the outputs is provided below.

Features Low Side Output High Side Output
Operating Voltage Range 0 – 36 V 5 – 36 V
Maximum Load Voltage 40 V 40 V
ON-State Resistance 50 mΩ 100 mΩ (per channel)
Recommended Load Current 3 A 3 A
Short Circuit Detection No protection No protection
Diagnostic Functions NA NA
Recommended Switching DO: On/off
PWM: 0-20 kHz (10%-90% duty cycle)		 DO: On/off
PWM: 0-12 kHz (10%-90% duty cycle)
Status Feedback NA NA
Load Types Recommended Resistive Resistive

Information on DO

Each digital output pin on the FlexCase is configurable for high-side or low-side operation.

Half Bridge Configuration

The diagram below shows the configuration for Digital Output Bank 1. Banks 2 and 3 are nearly identical in implementation.

 

 

A Half Bridge (or) a H-bridge is an electronic circuit designed to reverse the polarity of voltage applied to a load. These circuits are commonly utilized in robotics and various applications to enable DC motors to operate in both forward and reverse directions.

Recommendation for Integration

  • Low Side Drive:
    • Whenever possible, low side drive is recommended.
  • High Side Drive:
    • For general high side drive, use outputs 1 through 10.
  • High Side PWM:
    • Use outputs 11 through 16 only if high side PWM is required.
    • Note: Outputs 11 through 16 have a known high side issue and can be damaged if not integrated with care.

Configuration and Use

  • Drive Activation:
    • Low side drive is active high.
    • High side drive is active low.
    • Important: You must supply a voltage on the high side supply for high side drive to function.
  • Critical Warning:
    • If both high and low side drive are active at the same time, the output will be destroyed.
  • Permissible Output Pin States:
    • Permissible output pin states are shown in the table below, using Digital Output 1 (DO1 EXT) as an example.
    High Side Setpoint Low Side Setpoint
    PTD16 Unconfigured PTD16 Low PTD16 High
    PTD15 Unconfigured Open Circuit. No connection Open Circuit. No connection Output connected to GND
    PTD15 Low Output connected to +VCC Output connected to +VCC DANGER! CAN DAMAGE BOARD!
    PTD15 High Open Circuit. No connection Open Circuit. No connection Output connected to GND

 

  • High Side Supply Voltage:

Any voltage (within specified limits) can be supplied on the high side supply.

  • Examples:
    • The 5V output can be fed into the high side supply to create a 5V digital output.
    • A battery supply can be fed into the high side supply.