SLOS861C March   2015  – January 2023 DRV2700

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 Switching Characteristics
    7. 6.7 Typical characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Boost Converter and Control Loop
      2. 7.3.2 High-Voltage Amplifier
      3. 7.3.3 Fast Start-Up (Enable Pin)
      4. 7.3.4 Gain Control
      5. 7.3.5 Adjustable Boost Voltage
      6. 7.3.6 Adjustable Boost Current-Limit
      7. 7.3.7 Internal Charge Pump
      8. 7.3.8 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Boost + Amplifier Mode
      2. 7.4.2 Flyback Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 AC-Coupled DAC Input Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Piezo Load Selection
          2. 8.2.1.2.2  Programming The Boost Voltage
          3. 8.2.1.2.3  Inductor and Transformer Selection
          4. 8.2.1.2.4  Programing the Boost and Flyback Current-Limit
          5. 8.2.1.2.5  Boost Capacitor Selection
          6. 8.2.1.2.6  Pulldown FET and Resistors
          7. 8.2.1.2.7  Low-Voltage Operation
          8. 8.2.1.2.8  Current Consumption Calculation
          9. 8.2.1.2.9  Input Filter Considerations
          10. 8.2.1.2.10 Output Limiting Factors
          11. 8.2.1.2.11 Startup and Shutdown Sequencing
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Filtered AC Coupled Single-Ended PWM Input Application
      3. 8.2.3 DC-Coupled DAC Input Application
      4. 8.2.4 DC-Coupled Reference Input Application
      5. 8.2.5 Flyback Circuit
    3. 8.3 System Example
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Boost + Amplifier Configuration Layout Considerations
      2. 10.1.2 Flyback Configuration Layout Considerations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Trademarks
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RGP|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.2.1.2.2 Programming The Boost Voltage

The boost or flyback output voltage is programmed by an external network as shown in Figure 8-3.

GUID-115A8622-F12F-4640-86D6-7A522C3D1C4F-low.gifFigure 8-3 External Network

Depending on which configuration or mode is used in the system, use Equation 1 to calculate the output voltage.

Equation 1. GUID-5F19783C-733E-4072-A0DC-E532F5D59F33-low.gif

where

  • VFB = 1.30 V
  • VOP = VOL of the operational amplifier (op amp). Typically this can be approximated to 0 V.

The BST pin should be programmed to a value 5-V greater than the largest peak voltage in the system expected to allow adequate amplifier headroom. Because the programming range for the boost voltage extends to 105 V, the leakage current through the resistor divider becomes significant. TI recommends that the sum of the resistance of R(FB1) and R(FB2) be greater than 500 kΩ.

The flyback mode configuration may require filtering capacitors to go along with the feedback network to increase the performance at low and high frequencies. Because the charge storage is inversely proportional to the capacitance, use Equation 2 to calculate the values of the capacitors. In general, select a value of 22 pF for C(FB1).

For this design example, because the value of VPP must be negative, the boost + amplifier configuration must be used. Additionally, because the value of VBST must be 5 V more than VP, VBST is set to 65 V. Using Equation 1, the feedback resistors can be found such that RFB1 = 49 × RFB2. Because the total resistance must be greater than 500 kΩ, RFB1= 735 kΩ and RFB2= 15 kΩ.

Equation 2. GUID-6D90EA4A-8642-450D-86CB-5223DD57F850-low.gif
Note:

When resistor values greater than 1 MΩ are used, PCB contamination causes boost voltage inaccuracy. Use caution when soldering large resistences, and clean the area when finished for best results.