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Archive of posts published in the category: Circuit
May
9

Designing a Wide Voltage Range Automotive Circuit Protector

Ignition cranking during startup and load dumps during shutdown are common sources of voltage transients on an automotive supply line. These undervoltage (UV) and overvoltage (OV) transients can have significant magnitudes and will damage circuits that are not designed to operate during these extremes.

Specialized UV and OV protection devices have been developed to disconnect sensitive electronics from power supply transients. For example, protection devices can monitor the input supply using a window comparator and then validate that it is within range. Similarly, the supply voltage can be monitored by a resistive divider network connected to the UV and OV monitor pins. The window comparator output can then drive the gates of two N-channel MOSFETs that make or break the connection between the supply and the load. The window comparator can be designed with hysteresis on its monitor pins to improve noise immunity. Hysteresis can prevent false MOSFET on/off switching due to ripple or other high frequency oscillations on the supply line. For example, 25 mV of hysteresis is equivalent to 5% of the monitor pin thresholds and is common for UV and OV protection devices.

For their own protection or to reduce ignition loading, some automotive accessory circuits must be disconnected from the supply line during startup or shutdown. Due to the large transients involved, these circuits may require more hysteresis than the protection device can provide by itself. For such applications, the increased hysteresis requirement can be satisfied by matching the protection device with a supply monitor that has adjustable hysteresis. This article walks through how to design a wide voltage range automotive circuit protector.

Figure 1. Power path control with wide voltage monitor hysteresis

Automotive UV/OV and Overcurrent Monitor with Circuit Protection

The architecture shown in Figure 1 protects electronics that are sensitive to undervoltage, overvoltage, and overcurrent transients present on an automotive supply. Figure 1 is an example of a wide voltage range automotive circuit protector. In this circuit, an LTC4368  from Analog Devices serves as the specialized UV and OV protection device and is responsible for connecting the load to the supply. The role of the window comparator is managed by an LTC2966.

The LTC2966 monitors reverse voltage, undervoltage, and overvoltage conditions. Monitoring thresholds and hysteresis levels are configured by the resistor networks on the INH and INL pins and the voltages on the RS1 and RS2 pins. OUTA is the UV window comparator output and OUTB is the OV window comparator output. The polarity of these outputs can be selected to be inverting or noninverting with respect to the inputs via the PSA and PSB pins. In Figure 1, they are configured to be noninverting. The OUTA and OUTB outputs from the LTC2966 are pulled up to the REF pin of the LTC2966 and are fed directly to the UV and OV pins of the LTC4368.

The LTC4368 provides reverse current and overcurrent protection. The size of the current sense resistor, R11, determines the reverse current and overcurrent levels. The LTC4368 decides if the

Apr
17

2020 World Series of Poker Circuit Bicycle Casino Series Kicks Off Feb. 29

The World Series of Poker Circuit is heading back to the Bicycle Hotel & Casino from Feb. 29 through March 31, with thirteen gold ring events included. The centerpiece of the whole affair is the 2020 WSOP Circuit Bicycle Casino $1,700 buy-in no-limit hold’em main event which kicks off with the first of two starting flights beginning on Sunday, March 15 at noon local time.

Players will begin with 30,000 in chips with initial blinds of 100-100 in the event. Blind levels will be 40 minutes long throughout the starting days but will increase to 60 minutes in length on day 2. Players can re-enter the event once per starting day.

Those that survive day 2 will return at noon on Wednesday, March 18 to play down to a champion. The final table will be streamed on Live At The Bike.

March 2019 WSOPC main event champion Sean YuThe March 2019 running of this WSOP Circuit main event drew a total of 678 entries to create a $1,027,170 final prize pool. Sean Yu emerged victorious, defeating Andrew Moreno heads-up to secure the ring and the top prize of $210,585.

Other past champions of WSOPC main event at the Bike include the likes of Dylan Wilkerson ($216,790), Antonio Esfandiari ($226,785), Jared Jaffee ($211,220), and Freddy Deeb ($171,810), who won the first-ever WSOP Circuit main event held at the Casino.

In addition to the WSOP Circuit events, the series will also play host to two massive $1,000,000 guaranteed events: The Quantum Millions (running Feb. 29 – March 9) and the Quantum Mega Millions XXII (running March 20 – Apr. 2).

Players interested in staying at The Bicycle Hotel and Casino during this series can take advantage of a WSOP Circuit player discounted room rate of $159 per night for a deluxe room with the promo code “WSOP” when selecting their stay. Click the banner image below to reserve your room today!

In late 2015 the Bicycle Hotel and Casino unveiled a $50 million hotel expansion to the property. The 117,907-square-foot addition boasts 99 rooms, including 29 suites, as well as a multitude of amenities including the Bike Brewery, full spa and elevated outdoor pool deck with private cabanas. The poker room is an expansive 100,000 square feet, with 185 tables available.

For more information you can visit the WSOP Circuit or the Bicycle Hotel and Casino websites.

 

 

 

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