ZHCSM82A April 2022 – September 2023 TPS38
PRODUCTION DATA
This design requires voltage supervision on an AC, with a known operating frequency, power supply rail. The undervoltage fault sensing is achieved by monitoring the DC output of a full bridge rectifier while the undervoltage fault is detected by inputting a half wave signal and its voltage frequency and magnitude are being monitored. The target output of this TPS38 application is for 5V reset logic.
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| PARAMETER | DESIGN REQUIREMENT | DESIGN RESULT |
|---|---|---|
| Power rail voltage Supervision | Monitor 24 VAC 800 Hz power supply for undervoltage conditions. Trigger undervoltage fault at 5 V and at 25.5 V. | TPS38 provides voltage monitoring with 1.5% max accuracy with adjustable/non-adjustable variations. |
| Maximum input voltage | Operate with power supply input up to 34 V. | The TPS38 can support a VDD of up to 65 V. |
| Output logic voltage | Open-Drain Output Topology | An open-drain output is recommended to provide the a 5 V reset signal. |
| SENSE1 delay when a fault is detected | RESET1 delay of at least 1.28 ms | CCTS1 = 10 nF sets 1.28 ms delay |
| SENSE2 delay when a fault is detected | RESET2 delay of at least 0.625 ms which is the time between half wave cycles | CCTS2 = 5.6 nF sets 717 μs delay |
| RESET1 delay when returning from a fault | RESET1 delay of at least 12.8 ms | CCTR1 = 10 nF sets 12.8 ms delay |
| Voltage monitor accuracy | Maximum voltage monitor accuracy of 1.5%. | The TPS38 has 1.5% maximum voltage monitor accuracy. |