MP6570 Specification clarification

Motor Drivers/Sensors
1
  1. Purpose of Test pin is not clear
  2. VDC and IDC pins connection / circuit is not clear under evaluation board or the datasheet.
  3. VDCCON pins is interlinked to DC bus fault but will it remain low / high or HIGH Z under normal operation ?
  4. RS485 under MP6570 EVALUATION KIT document has MAX3632 - Half duplex : 20000 Data Rate (kbps) (min)
    Baud rate = (40000000/39 [0027H Default]) - 1 = 1025640.025641026 Bits/sec
    the baud rate is a non-standard value set as default.
    Can it support full duplex RS458 interface ?
    Maximum baud rate it can support ?

with warm regards
Vasanthakumar M

2

Hi Vasanthakumar,

Welcome to the MPS Technical Forum. I’ll start working with our product line to get your questions answered. Will post an update in about 2-3 days.

3
  1. Purpose of Test pin is not clear Datasheet simply says to leave this pin floating. What is the purpose of this pin?

This pin is used for test signal output during ATE test. It’s ok to left it floating in real applications.

  1. VDC and IDC pins connection / circuit is not clear under evaluation board or the datasheet. What is the function of these pins and how should they be connected?

VDC is used to sense the DC input voltage to work with VDCCON pin to avoid voltage spikes when mechanical energy is recycled back to electrical energy (this may happen when motor speed decrease). Use a resistor divider from the bus voltage to GND and connect the center node to the VDC pin directly to sense the DC voltage.

IDC is used to sense the DC input current. See datasheet page 38 and page 39 for more detail.

  1. VDCCON pins is interlinked to DC bus fault but will it remain low / high or HIGH Z under normal operation ?

During normal operation, it will remain low. Only when the DC link voltage (sensed by VDC pin) is higher than the setting threshold (VIN_LIMIT). See page 37 and page 38 for more detail.

  1. RS485 under MP6570 EVALUATION KIT document has MAX3632 - Half duplex : 20000 Data Rate (kbps) (min)
    Baud rate = (40000000/39 [0027H Default]) - 1 = 1025640.025641026 Bits/sec
    the baud rate is a non-standard value set as default.
    Can it support full duplex RS458 interface ?
    Maximum baud rate it can support ?

The baudrate can be set by register 34h. This register can be programed as customer requirements. The maximum tested baudrate is 4Mbps, this is also limited by the RS485 transceiver.

The protocol of MP6570 is half duplex. There may be no performance improvement if using duplex interface. See page 45 for more detail.

4

Hi,

Thanks a lot for your support. Got clarity.

with warm regards
Vasanthakumar M