SLVSHO3 April   2024 DRV8235

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 I2C Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Operating Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 External Components
      2. 7.3.2 Summary of Features
      3. 7.3.3 Bridge Control
      4. 7.3.4 Current Sense and Regulation (IPROPI)
        1. 7.3.4.1 Current Sensing
        2. 7.3.4.2 Current Regulation
          1. 7.3.4.2.1 Fixed Off-Time Current Regulation
          2. 7.3.4.2.2 Cycle-By-Cycle Current Regulation
      5. 7.3.5 Stall Detection
      6. 7.3.6 Motor Voltage and Speed Regulation
        1. 7.3.6.1 Internal Bridge Control
        2. 7.3.6.2 Setting Speed/Voltage Regulation Parameters
          1. 7.3.6.2.1 Speed and Voltage Set
          2. 7.3.6.2.2 Speed Scaling Factor
            1. 7.3.6.2.2.1 Target Speed Setting Example
          3. 7.3.6.2.3 Motor Resistance Inverse
          4. 7.3.6.2.4 Motor Resistance Inverse Scale
          5. 7.3.6.2.5 KMC Scaling Factor
          6. 7.3.6.2.6 KMC
          7. 7.3.6.2.7 VSNS_SEL
        3. 7.3.6.3 Soft-Start and Soft-Stop
          1. 7.3.6.3.1 TINRUSH
      7. 7.3.7 Protection Circuits
        1. 7.3.7.1 Overcurrent Protection (OCP)
        2. 7.3.7.2 Thermal Shutdown (TSD)
        3. 7.3.7.3 VM Undervoltage Lockout (VM UVLO)
        4. 7.3.7.4 Overvoltage Protection (OVP)
        5. 7.3.7.5 nFAULT Output
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Low-Power Sleep Mode
      3. 7.4.3 Fault Mode
    5. 7.5 Programming
      1. 7.5.1 I2C Communication
        1. 7.5.1.1 I2C Write
        2. 7.5.1.2 I2C Read
  9. 8 Register Map
    1. 8.1 DRV8235_STATUS Registers
    2. 8.2 DRV8235_CONFIG Registers
    3. 8.3 DRV8235_CTRL Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application: Brushed DC Motor
      1. 9.2.1 Design Requirements
      2. 9.2.2 Stall Detection
        1. 9.2.2.1 Application Description
          1. 9.2.2.1.1 Stall Detection Timing
          2. 9.2.2.1.2 Hardware Stall Threshold Selection
      3. 9.2.3 Motor Speed and Voltage Regulation Application
        1. 9.2.3.1 Tuning Parameters
          1. 9.2.3.1.1 Resistance Parameters
          2. 9.2.3.1.2 KMC and KMC_SCALE
            1. 9.2.3.1.2.1 Case I
            2. 9.2.3.1.2.2 Case II
              1. 9.2.3.1.2.2.1 Method 1: Tuning from Scratch
                1. 9.2.3.1.2.2.1.1 Tuning KMC_SCALE
                2. 9.2.3.1.2.2.1.2 Tuning KMC
              2. 9.2.3.1.2.2.2 Method 2: Using the Proportionality factor
                1. 9.2.3.1.2.2.2.1 Working Example
      4. 9.2.4 Motor Voltage
      5. 9.2.5 Motor Current
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Bulk Capacitance
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3 DRV8235_CTRL Registers

Table 8-21 lists the memory-mapped registers for the DRV8235_CTRL registers. All register offset addresses not listed in Table 8-21 should be considered as reserved locations and the register contents should not be modified.

Table 8-21 DRV8235_CTRL Registers
OffsetAcronymRegister NameSection
EhREG_CTRL0Regulation control registers (1/3).Section 8.3.1
FhREG_CTRL1Regulation control registers (2/3).Section 8.3.2
10hREG_CTRL2Regulation control registers (3/3).Section 8.3.3
11hRC_CTRL0Control Registers - (1/9).Section 8.3.4
12hRC_CTRL1Control Registers - (2/9).Section 8.3.5
13hRC_CTRL2Control Registers - (3/9).Section 8.3.6
14hRC_CTRL3Control Registers - (4/9).Section 8.3.7
15hRC_CTRL4Control Registers - (5/9).Section 8.3.8
16hRC_CTRL5Control Registers - (6/9).Section 8.3.9
17hRC_CTRL6Control Registers - (7/9).Section 8.3.10
18hRC_CTRL7Control Registers - (8/9).Section 8.3.11
19hRC_CTRL8Control Registers - (9/9).Section 8.3.12

Complex bit access types are encoded to fit into small table cells. Table 8-22 shows the codes that are used for access types in this section.

Table 8-22 DRV8235_CTRL Access Type Codes
Access TypeCodeDescription
Read Type
RRRead
Write Type
WWWrite
Reset or Default Value
-nValue after reset or the default value

8.3.1 REG_CTRL0 Register (Offset = Eh) [Reset = 27h]

REG_CTRL0 is shown in Table 8-23.

Return to the Summary Table.

Set features like Soft Start/Stop and speed scaling factor.

Table 8-23 REG_CTRL0 Register Field Descriptions
BitFieldTypeResetDescription
7-6RSVDR0h Reserved.
5EN_SSR/W1h Used to enable/disable soft start/stop.
1b: Target motor voltage or speed is soft-started and soft-stopped over the duration of tINRUSH time.
0b: Soft-start/stop feature is disabled.
Refer to Section 7.3.6.3 for further explanation.
4-3REG_CTRLR/W0h Selects the current regulation scheme (fixed off-time or cycle-by-cycle) or motor speed and voltage regulation.
00b: Fixed Off-Time Current Regulation.
01b: Cycle-By-Cycle Current Regulation.
10b: Motor speed is regulated.
11b: Motor voltage is regulated.
Refer to Section 7.3.4.2 for further explanation.
2PWM_FREQR/W1h Sets the PWM frequency when bridge control is configured by INx bits (I2C_BC=1b).
0b: PWM frequency is set to 50kHz.
1b: PWM frequency is set to 25kHz.
1-0W_SCALER/W3h Scaling factor that helps in setting the target motor current ripple speed.
00b: 16
01b: 32
10b: 64
11b: 128
Refer to Section 7.3.6.2.2 for further explanation.

8.3.2 REG_CTRL1 Register (Offset = Fh) [Reset = FFh]

REG_CTRL1 is shown in Table 8-24.

Return to the Summary Table.

Set the target motor voltage and speed.

Table 8-24 REG_CTRL1 Register Field Descriptions
BitFieldTypeResetDescription
7-0WSET_VSETR/WFFh Sets the target motor voltage or current ripple speed.
A detailed explanation is provided in Section 7.3.6.2.1.

8.3.3 REG_CTRL2 Register (Offset = 10h) [Reset = 00h]

REG_CTRL2 is shown in Table 8-25.

Return to the Summary Table.

Set the duty cycle and cut-off frequency for output voltage filtering.

Table 8-25 REG_CTRL2 Register Field Descriptions
BitFieldTypeResetDescription
7-6OUT_FLTR/W0h Programs the cut-off frequency of the output voltage filtering.
00b: 250Hz
01b: 500Hz
10b: 750Hz
11b: 1000Hz
For best results, choose a cut-off frequency equal to a value at least 20 times lower than the PWM frequency. Eg, if you PWM at 20kHz, OUT_FLT=11b (1000Hz) is sufficient.
5-0PROG_DUTYR/W0h When speed/voltage regulation is inactive and DUTY_CTRL is set to 1b, the user can write the desired PWM duty cycle to this register. The range of duty cycle is 0% (000000b) to 100% (111111b).

8.3.4 RC_CTRL0 Register (Offset = 11h) [Reset = 01h]

RC_CTRL0 is shown in Table 8-26.

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Reserved.

Table 8-26 RC_CTRL0 Register Field Descriptions
BitFieldTypeResetDescription
7-0RSVDR/W1h Reserved.

8.3.5 RC_CTRL1 Register (Offset = 12h) [Reset = FFh]

RC_CTRL1 is shown in Table 8-27.

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Reserved.

Table 8-27 RC_CTRL1 Register Field Descriptions
BitFieldTypeResetDescription
7-0RSVDR/WFFh Reserved.

8.3.6 RC_CTRL2 Register (Offset = 13h) [Reset = 73h]

RC_CTRL2 is shown in Table 8-28.

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Set values of various scaling parameters.

Table 8-28 RC_CTRL2 Register Field Descriptions
BitFieldTypeResetDescription
7-6INV_R_SCALER/W1h Scaling factor for the INV_R parameter.
00b: INV_R_SCALE = 2
01b: INV_R_SCALE = 64
10b: INV_R_SCALE = 1024
11b: INV_R_SCALE = 8192
Refer to Section 7.3.6.2.4 for further explanation.
5-4KMC_SCALER/W3h Scaling factor for KMC parameter.
00b: KMC_SCALE = 24 x 28
01b: KMC_SCALE = 24 x 29
10b: KMC_SCALE = 24 x 212
11b: KMC_SCALE = 24 x 213
Refer to Section 7.3.6.2.5 for further explanation.
3-0RSVDR/W3h Reserved.

8.3.7 RC_CTRL3 Register (Offset = 14h) [Reset = 00h]

RC_CTRL3 is shown in Table 8-29.

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Set the INV_R parameter.

Table 8-29 RC_CTRL3 Register Field Descriptions
BitFieldTypeResetDescription
7-0INV_RR/W0h User input based on motor coil resistance.
INV_R = INV_R_SCALE / Motor Resistance. Must not be set to 0. Refer to Section 7.3.6.2.3 for further explanation.

8.3.8 RC_CTRL4 Register (Offset = 15h) [Reset = 00h]

RC_CTRL4 is shown in Table 8-30.

Return to the Summary Table.

Set the KMC parameter.

Table 8-30 RC_CTRL4 Register Field Descriptions
BitFieldTypeResetDescription
7-0KMCR/W0h Represents a proportional value of the motor back emf constant.
KMC = (KV) / NR)*KMC_SCALE.
Refer to Section 7.3.6.2.6 for further explanation.

8.3.9 RC_CTRL5 Register (Offset = 16h) [Reset = 00h]

RC_CTRL5 is shown in Table 8-31.

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Reserved.

Table 8-31 RC_CTRL5 Register Field Descriptions
BitFieldTypeResetDescription
7-0RSVDR0h Reserved.

8.3.10 RC_CTRL6 Register (Offset = 17h) [Reset = 00h]

RC_CTRL6 is shown in Table 8-32.

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Reserved.

Table 8-32 RC_CTRL6 Register Field Descriptions
BitFieldTypeResetDescription
7-0RSVDR/W0h Reserved.

8.3.11 RC_CTRL7 Register (Offset = 18h) [Reset = 21h]

RC_CTRL7 is shown in Table 8-33.

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Set the proportional constant in PI control loop.

Table 8-33 RC_CTRL7 Register Field Descriptions
BitFieldTypeResetDescription
7-5KP_DIVR/W1h Used to select a division value for calculating the actual proportional constant for the PI control loop.
Actual proportional constant, KP = KP_MULT/KP_DIV.
Settings are as follows:
000b: 32
001b: 64
010b: 128
011b: 256
100b: 512
101b: 16
110b: 1
4-0KP_MULTR/W1h Represents the PI loop KP constant. This is not the actual proportional constant that is fed into the gain block of the PI control loop. Rather, the actual proportional constant can be calculated using the value of this register.
Actual Proportional Constant, KP = KP_MULT/KP_DIV.
For example, if actual proportional constant is 0.0625, then KP_MULT can be set to 1 (00001b), and KP_DIV can be set to 16 (corresponds to 101b), hence,
Actual proportional constant = 1/16 = 0.0625.

8.3.12 RC_CTRL8 Register (Offset = 19h) [Reset = 21h]

RC_CTRL8 is shown in Table 8-34.

Return to the Summary Table.

Set the integral constant in PI control loop.

Table 8-34 RC_CTRL8 Register Field Descriptions
BitFieldTypeResetDescription
7-5KI_DIVR/W1h Used to select a division value for calculating the actual integral constant for the PI control loop.
Actual integral constant, I = KI_MULT/KI_DIV.
Settings are as follows:
000b: 32
001b: 64
010b: 128
011b: 256
100b: 512
101b: 16
110b: 1
4-0KI_MULTR/W1h Represents the PI loop KI constant. This is not the actual integral constant that is fed into the gain block of the PI control loop. Rather, the actual integral constant can be calculated using the value of this register.
Actual Integral Constant, I = KI_MULT/KI_DIV.
For example, if actual integral constant is 0.90625, then KI_MULT can be set to 29 (11101b), and KI_DIV can be set to 32 (corresponds to 000b), hence,
Actual integral constant = 29/32 = 0.90625.