ZHCSM65 March 2022 TPS629203-Q1
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
-
8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Feature Description
- 8.3.1 Mode Selection and Device Configuration (MODE/S-CONF Pin)
- 8.3.2 Adjustable VO Operation (External Voltage Divider)
- 8.3.3 Selectable VO Operation (VSET and Internal Voltage Divider)
- 8.3.4 Smart Enable with Precise Threshold
- 8.3.5 Power Good (PG)
- 8.3.6 Output Discharge Function
- 8.3.7 Undervoltage Lockout (UVLO)
- 8.3.8 Current Limit and Short Circuit Protection
- 8.3.9 Thermal Shutdown
- 8.4 Device Functional Modes
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
8.4.3 AEE (Automatic Efficiency Enhancement)
When the MODE/S-CONF pin is configured for auto PFM/PWM with AEE mode, the TPS629203-Q1 provides the highest efficiency over the entire input voltage and output voltage range by automatically adjusting the switching frequency of the converter (see Equation 8). To keep the efficiency high over the entire duty cycle range, the switching frequency is adjusted while maintaining the ripple current amplitudes. This feature compensates for the very small duty cycles of high VIN to low VOUT conversions, which can limit the control range in other topologies.
Traditionally, the efficiency of a switched mode converter decreases if VOUT decreases, VIN increases, or both. By decreasing the switching losses at lower VOUT values or higher VIN values, the AEE feature provides an efficiency enhancement across various duty cycles, especially for the lower VOUT values, where fixed frequency converters suffer from a significant efficiency drop. Furthermore, when used with the recommended 2.2-μH inductor, the ripple current amplitudes remains low enough to deliver the full output current without reaching current limit across the entire range of input and output voltages (see Figure 8-4).
By using the same TON configuration (see Equation 9) across the entire load range in AEE mode, the inductor ripple current in AEE mode becomes effectively independent of the output voltage and can be approximated by Equation 9:
| L = 2.2 μH | Fsw = 2.5 MHz | Auto PFM/PWM with AEE |
The TPS629203-Q1 operates in AEE mode as long as the output current is higher than half the ripple current of the inductor. To maintain high efficiency at light loads, the device enters power save mode at the boundary to discontinuous mode (DCM), which happens when the output current becomes smaller than half the inductor ripple current.