ZHCSHD3K October 2017 – July 2024 BQ2980 , BQ2982
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 4 Device Comparison Table
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Overvoltage (OV) Status
- 7.3.2 Undervoltage (UV) Status
- 7.3.3 Overcurrent in Charge (OCC) Status
- 7.3.4 Overcurrent in Discharge (OCD) and Short Circuit in Discharge (SCD) Status
- 7.3.5 Overtemperature (OT) Status
- 7.3.6 Charge and Discharge Driver
- 7.3.7 CTR for FET Override and Device Shutdown
- 7.3.8 CTR for PTC Connection
- 7.3.9 ZVCHG (0-V Charging)
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Revision History
- 13Mechanical, Packaging, and Orderable Information
7.3.7 CTR for FET Override and Device Shutdown
The CTR pin is an active-high input pin, which can be controlled by the host system to turn off both CHG and DSG outputs momentarily to reset the system, shut down the system for low-power storage, or as a necessary shutdown if the host detects a critical system error.
The CTR pin uses a 4.5-s timer (same specification tolerance as the tOVP delay 4.5-s option) to differentiate a reset and shutdown signal. CHG and DSG are off when VCTR > CTR VIH for > 200 µs. Counting from the start of VCTR > VIH, if VCTR drops below VIL within 3.6 s, CHG and DSG simply turn back on. If CTR remains HIGH for > 5.4 s, the device enters SHUTDOWN mode.
With this timing control, the system designer can use an RC circuit to implement either a host-controlled power-on-reset or a system shutdown.
Figure 7-1 CTR Level in Rising and Falling Direction- CTR shuts down the device only when VCTR is HIGH for > 5.4 s AND when there is no OV or OT fault present.
- The CTR VIH level is the voltage level at which the CTR pin is considered HIGH in the positive direction as voltage increases. There is a minimum hysteresis designed into the logic level; therefore, as voltage decreases, CTR is considered HIGH at the (VIH – VHYS) level.
- The FET override and the shutdown functions are not available if the CTR pull-up is enabled. See Section 7.3.8 for details.
Figure 7-2 System Reset Function Implementation
Figure 7-3 Potential System- Controlled Shutdown Implementation