ZHCSHS5B February 2018 – February 2024 UCC21222
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 4 Pin Configuration and Functions
-
5 Specifications
- 5.1 Absolute Maximum Ratings
- 5.2 ESD Ratings
- 5.3 Recommended Operating Conditions
- 5.4 Thermal Information
- 5.5 Power Ratings
- 5.6 Insulation Specifications
- 5.7 Safety-Related Certifications
- 5.8 Safety-Limiting Values
- 5.9 Electrical Characteristics
- 5.10 Switching Characteristics
- 5.11 Thermal Derating Curves
- 5.12 Typical Characteristics
- 6 Parameter Measurement Information
- 7 Detailed Description
-
8 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 Custom Design With WEBENCH® Tools
- 8.2.2.2 Designing INA/INB Input Filter
- 8.2.2.3 Select Dead Time Resistor and Capacitor
- 8.2.2.4 Select External Bootstrap Diode and its Series Resistor
- 8.2.2.5 Gate Driver Output Resistor
- 8.2.2.6 Estimating Gate Driver Power Loss
- 8.2.2.7 Estimating Junction Temperature
- 8.2.2.8 Selecting VCCI, VDDA/B Capacitor
- 8.2.2.9 Application Circuits with Output Stage Negative Bias
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Revision History
- 13Mechanical, Packaging, and Orderable Information
7.4.2.2 Connecting a Programming Resistor between DT and GND Pins
Program tDT by placing a resistor, RDT, between the DT pin and GND. The appropriate RDT value can be determined from:
where
- tDT is the programmed dead time, in nanoseconds.
- RDT is the value of resistance between DT pin and GND, in kilo-ohms.
The steady state voltage at the DT pin is about 0.8 V. RDT programs a small current at this pin, which sets the dead time. As the value of RDT increases, the current sourced by the DT pin decreases. The DT pin current will be less than 10 µA when RDT = 100 kΩ. For larger values of RDT, TI recommends placing RDT and a ceramic capacitor, 2.2 nF or greater, as close to the DT pin as possible to achieve greater noise immunity and better dead time matching between both channels.
The falling edge of an input signal initiates the programmed dead time for the other signal. The programmed dead time is the minimum enforced duration in which both outputs are held low by the driver. The outputs may also be held low for a duration greater than the programmed dead time, if the INA and INB signals include a dead time duration greater than the programmed minimum. If both inputs are high simultaneously, both outputs will immediately be set low. This feature is used to prevent shoot-through in half-bridge applications, and it does not affect the programmed dead time setting for normal operation. Various driver dead time logic operating conditions are illustrated and explained in Figure 7-4.
Figure 7-4 Input and Output Logic
Relationship with Input SignalsCondition A: INB goes low, INA goes high. INB sets OUTB low immediately and assigns the programmed dead time to OUTA. OUTA is allowed to go high after the programmed dead time.
Condition B: INB goes high, INA goes low. Now INA sets OUTA low immediately and assigns the programmed dead time to OUTB. OUTB is allowed to go high after the programmed dead time.
Condition C: INB goes low, INA is still low. INB sets OUTB low immediately and assigns the programmed dead time for OUTA. In this case, the input signal dead time is longer than the programmed dead time. When INA goes high after the duration of the input signal dead time, it immediately sets OUTA high.
Condition D: INA goes low, INB is still low. INA sets OUTA low immediately and assigns the programmed dead time to OUTB. In this case, the input signal dead time is longer than the programmed dead time. When INB goes high after the duration of the input signal dead time, it immediately sets OUTB high.
Condition E: INA goes high, while INB and OUTB are still high. To avoid overshoot, OUTB is immediately pulled low. After some time OUTB goes low and assigns the programmed dead time to OUTA. OUTB is already low. After the programmed dead time, OUTA is allowed to go high.
Condition F: INB goes high, while INA and OUTA are still high. To avoid overshoot, OUTA is immediately pulled low. After some time OUTA goes low and assigns the programmed dead time to OUTB. OUTA is already low. After the programmed dead time, OUTB is allowed to go high.