3 External Amplifier

Some motor control development boards (see Table ) are equipped with Operational Amplifiers to amplify the motor phase currents and DC bus current (external Op Amp configuration). To obtain information on amplifier gain, see the user’s guide of the specific development board.

The external amplifier outputs from the development board and the internal amplifier outputs of the dsPIC® DSC are connected to a single analog channel on the DIM.

The DIM is configured to use the internal amplifier outputs of the dsPIC® DSC by default. Table 3-1 summarizes the jumper resistors to be populated and removed to convert the DIM from “internal Op Amp configuration” to “external Op Amp configuration” or vice versa.
Table 3-1. Selection Between Internal and External Amplifier Configuration
Operational AmplifierJumper Resistor (0R) Settings on the DIMFirmware Setting
Internal Amplifier Configuration (default)External Amplifier Configuration
PopulateRemovePopulateRemove
OA2R27R39R39R27
  • Configure and enable internal amplifiers in “internal Op Amp configuration”.
  • Ensure the internal amplifiers are disabled in the “external Op Amp configuration”.
OA3R29, R36R41R41R29, R36
Figure 3-1. Jumper Resistors (0R) on the DIM for Amplifier Output Selection