SLUSCU0J March   2018  – March 2022 BQ77915


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Device Comparison Table
  7. Pin Configuration and Functions
  8. Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Typical Characteristics
  9. Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Device Functionality Summary
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Protection Summary
      2. 9.3.2  Fault Operation
        1.  Operation in OV
        2.  Operation in UV
        3.  Operation in OW
        4.  Operation in OCD1
        5.  Operation in OCD2
        6.  Programming the OCD1/2 Delay Using the OCDP Pin
        7.  Operation in SCD
        8.  Operation in OCC
        9.  Overcurrent Recovery Timer
        10. Load Detection and Load Removal Detection
        11. Operation in OTC
        12. Operation in OTD
        13. Operation in UTC
        14. Operation in UTD
      3. 9.3.3  Protection Response and Recovery Summary
      4. 9.3.4  Cell Balancing
      5. 9.3.5  HIBERNATE Mode Operation
      6. 9.3.6  Configuration CRC Check and Comparator Built-In-Self-Test
      7. 9.3.7  Fault Detection Method
        1. Filtered Fault Detection
      8. 9.3.8  State Comparator
      9. 9.3.9  DSG FET Driver Operation
      10. 9.3.10 CHG FET Driver Operation
      11. 9.3.11 External Override of CHG and DSG Drivers
      12. 9.3.12 Configuring 3-Series, 4-Series, or 5-Series Modes
      13. 9.3.13 Stacking Implementations
      14. 9.3.14 Zero-Volt Battery Charging Inhibition
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power Modes
        1. Power On Reset (POR)
        2. NORMAL Mode
        3. FAULT Mode
        4. HIBERNATE Mode
        5. SHUTDOWN Mode
        6. Customer Fast Production Test Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Recommended System Implementation
        1. CHG and DSG FET Rise and Fall Time
        2. Protecting CHG and LD
        3. Protecting the CHG FET
        4. Using Load Detect for UV Fault Recovery
        5. Temperature Protection
        6. Adding RC Filters to the Sense Resistor
        7. Using the State Comparator in an Application
          1. Examples
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. Design Example
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Third-Party Products Disclaimer
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

External Override of CHG and DSG Drivers

The device allows direct disabling of the CHG and DSG drivers through the CTRC and CTRD pins, respectively. Figure 9-10 shows the operation of the CTRC and CTRD pins. To support the simple-stack solution for higher-cell count packs, these pins are designed to operate above the device’s VDD level. Connect a 10-MΩ resistor between a lower device CTRC and CTRD input pins to an upper device's CHG and DSG output pins (see the schematics in Section 9.3.13).

CTRC only enables or disables the CHG pin, while CTRD only enables or disables the DSG pin. When the CTRx pin is in the DISABLED region, the respective FET pin will be off, regardless of the state of the protection circuitry. When the CTRx pin is in either ENABLED region, the protection circuitry determines the state of the FET driver.


In any event where CTRC is disabled, CTRD is enabled, no DSG FET related faults are present, and (SRP–SRN) < VSTATE_D, the CHG output pin will be held high regardless. In any event where CTRD is disabled, CTRC is enabled, no charge FET related faults present, and (SRP–SRN) > VSTATE_C, the DSG output pin will be held high regardless.

Both CTRx pins apply the fault-detection filtered method to improve the robustness of the signal detection. The counter counts up if an ENABLED signal is sampled; the counter counts down if a DISABLED signal is sampled. When the counter counts up from 0% to > 70% of its full range, which takes about 7-ms typical of a solid signal, the CTRx pins take the signal as ENABLED. If the counter counts down from 100% to < 30% of its full range, which takes about 7-ms typical of a solid signal, the CTRx pins take the signal as DISABLED. From a 0 count counter (solid DISABLE), a solid ENABLE signal takes about tCTRDEG_ON time to deglitch. From a 100% count (solid ENABLE), a solid DISABLE signal takes about tCTRDEG_OFF time to deglitch. Although such a filter scheme provides a certain level of noise tolerance, it is highly recommended to shield the CTRx traces and keep the traces as short as possible in the PCB layout design. The CTRx deglitch time will add onto the FET response timing on OV, UV, and OW faults in a stack configuration. The tCTRDEG_OFF time adds an additional delay to the fault detection timing and the tCTRDEG_ON time adds an additional delay to the fault recovery timing.

GUID-51FE90DA-EEB0-4E90-AE61-E3C066F4AA28-low.gifFigure 9-10 CTRC, CTRD Voltage Levels