ZHCSNM6A May 2021 – August 2021 TPS6521855
PRODUCTION DATA
- 1 特性
- 2 应用
- 3 说明
- 4 Revision History
- 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
Wake-Up and Power-Up and Power-Down Sequencing
- 7.3.1.1 Power-Up Sequencing
- 7.3.1.2 Power-Down Sequencing
- 7.3.1.3 Strobe 1 and Strobe 2
- 7.3.1.4 Supply Voltage Supervisor and Power-Good (PGOOD)
- 7.3.1.5 Internal LDO (INT_LDO)
- 7.3.1.6 Current Limited Load Switches
- 7.3.1.7 LDO1
- 7.3.1.8 UVLO
- 7.3.1.9 Power-Fail Comparator
- 7.3.1.10 DCDC3 and DCDC4 Power-Up Default Selection
- 7.3.1.11 I/O Configuration
- 7.3.1.12 Push Button Input (PB)
- 7.3.1.13 AC_DET Input (AC_DET)
- 7.3.1.14 Interrupt Pin (INT)
- 7.3.1.15 I2C Bus Operation
- 7.3.1
Wake-Up and Power-Up and Power-Down Sequencing
- 7.4 Device Functional Modes
- 7.5 Register Maps
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
7.3.1.5 Internal LDO (INT_LDO)
The internal LDO (INT_LDO) provides a regulated voltage to the internal digital core and analog circuitry. The internal LDO has a nominal output voltage of 2.5 V and can support up to 10 mA of external load.
When system power fails, the UVLO comparator triggers the power-down sequence. If system power drops below 2.3 V, the digital core is reset and all remaining power rails are shut down instantaneously and are pulled low to ground by their internal discharge circuitry (DCDC1-4 and LDO1).
The internal LDO reverse blocks to prevent the discharging of the output capacitor (CINT_LDO) on the INT_LDO pin. The remaining charge on the INT_LDO output capacitor provides a supply for the power rail discharge circuitry to ensure the outputs are discharged to ground even if the system supply has failed. The amount of hold-up time specified in GUID-7E74B44F-7C67-473D-A877-6F22434F1BCC.html#GUID-7E74B44F-7C67-473D-A877-6F22434F1BCC is a function of the output capacitor value (CINT_LDO) and the amount of external load on the INT_LDO pin, if any. The design allows for enough hold-up time to sufficiently discharge DCDC1-4, and LDO1 to ensure proper processor power-down sequencing.
Figure 7-9 Internal
LDO and UVLO Sensing