ZHCSJY8E june 2019 – february 2021 UCC256402 , UCC256403 , UCC256404
PRODUCTION DATA
- 1 特性
- 2 應(yīng)用
- 3 說明
- 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
- 7.4
Device Functional Modes
- 7.4.1 High Voltage Start-Up
- 7.4.2 X-Capacitor Discharge
- 7.4.3 Burst Mode Control
- 7.4.4
System State Machine
-
Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 LLC Power Stage Requirements
- 8.2.2.2 LLC Gain Range
- 8.2.2.3 Select Ln and Qe
- 8.2.2.4 Determine Equivalent Load Resistance
- 8.2.2.5 Determine Component Parameters for LLC Resonant Circuit
- 8.2.2.6 LLC Primary-Side Currents
- 8.2.2.7 LLC Secondary-Side Currents
- 8.2.2.8 LLC Transformer
- 8.2.2.9 LLC Resonant Inductor
- 8.2.2.10 LLC Resonant Capacitor
- 8.2.2.11 LLC Primary-Side MOSFETs
- 8.2.2.12 LLC Rectifier Diodes
- 8.2.2.13 LLC Output Capacitors
- 8.2.2.14 HV Pin Series Resistors
- 8.2.2.15 BLK Pin Voltage Divider
- 8.2.2.16 ISNS Pin Differentiator
- 8.2.2.17 VCR Pin Capacitor Divider
- 8.2.2.18 BW Pin Voltage Divider
- 8.2.2.19 Soft Start and Burst Mode Programming
- 8.2.3 Application Curves
-
Application and Implementation
- 8 Power Supply Recommendations
- 9 Layout
- 10Device and Documentation Support
封裝選項(xiàng)
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- DDB|14
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購(gòu)信息
7.3.6 Bulk Voltage Sensing
The BLK pin is used to sense the LLC DC input voltage (bulk voltage) level. The comparators on BLK pin have the following two thresholds:
- Bulk voltage level when LLC starts switching – VBLKStart
- Bulk voltage level when LLC stops switching – VBLKStop
A resistor divider is connected to the pin to achieve the desired system input range. A fault is triggered if BLK pin voltage drops lower than VBLKStop during operation. The detailed action of Input Under Voltage Protection is described in Section 7.3.9.4 section.
Figure 7-8 shows the block diagram of the BLK pin.
Figure 7-8 BLK Pin Block DiagramBLK voltage is also used to monitor the input over voltage fault for some device versions as listed in Section 5. There are two thresholds:
- Bulk voltage level when BLK over voltage protection (OVP) rising threshold - VBLKOVPRise
- Bulk voltage level when BLK over voltage protection (OVP) falling threshold - VBLKOVPFall
When BLK voltage is higher than VBLKOVPRise, OVP is triggered; OVP gets cleared when BLK voltage falls below VBLKOVPFall.