High-Voltage Gate Driver IC

Allegro A4900 Gate Driver IC

Allegro A4900 Gate Driver IC

The A4900 is a high-voltage brushless DC (BLDC) MOSFET gate driver IC. It is designed for high-voltage motor control for hybrid, electric vehicle, and 48-V automotive battery systems (e.g., electronic power steering, A/C compressors, fans, pumps, and blowers).

The A4900’s six gate drives can drive a range of N-channel insulated-gate bipolar transistors (IGBTs) or power MOSFET switches. The gate drives are configured as three high-voltage high-side drives and three low-side drives. The high-side drives are isolated up to 600 V to enable operation with high-bridge (motor) supply voltages. The high-side drives use a bootstrap capacitor to provide the supply gate drive voltage required for N-channel FETs. A TTL logic-level input compatible with 3.3- or 5-V logic systems can be used to control each FET.

A single-supply input provides the gate drive supply and the bootstrap capacitor charge source. An internal regulator from the single supply provides the logic circuit’s lower internal voltage. The A4900’s internal monitors ensure that the high- and low-side external FET’s gate source voltage is above 9 V when active.

The control inputs to the A4900 offer a flexible solution for many motor control applications. Each driver can be driven with an independent PWM signal, which enables implementation of all motor excitation methods including trapezoidal and sinusoidal drive. The IC’s integrated diagnostics detect undervoltage, overtemperature, and power bridge faults that can be configured to protect the power switches under most short-circuit conditions. Detailed diagnostics are available as a serial data word.

The A4900 is supplied in a 44-lead QSOP package and costs $3.23 in 1,000-unit quantities.

Allegro MicroSystems, LLC
www.allegromicro.com

CC277: (Re)Discovering Embedded

Authors in this issue range from a columnist who reintroduces us to the advantages of switched-capacitor filters to a frequent contributor who discusses his first encounter—and project—with the credit card-sized Raspberry Pi computer.

Columnist Robert Lacoste recently rediscovered one of his 1981 Elektor magazines, which included an article on switched-capacitor filters. “Since mastering switched-capacitor filters is now mandatory for many mixed-signal designs, I thought: Why not refresh the topic for a Circuit Cellar Darker Side article?” Lacoste says. Beginning on page 56, Lacoste shows you how to modify a simple one-pole RC filter into a switched-capacitor filter.

Frequent contributor Brian Millier placed his name on a waiting list to purchase his first Raspberry Pi. He finally received it in late 2012 and started the project that would inspire his two-part series “Raspberry Pi I/O?Board” (p. 42). The series explores the strengths and weaknesses of the single-board computer (SBC)?and explains the versatile I/O board he developed for it. “In the time since I received my Raspberry Pi, one of the board’s developers has designed an I/O board called the Gertboard. I feel my board is quite distinct and has some advantages over the Gertboard,” Millier says.

Speaking of the Raspberry Pi’s developers, this issue includes an interview with “RPi hardware guy” Peter Lomas (p. 38). He looks at the growth in popularity of the Raspberry Pi since its initial launch and shares how the nonprofit Raspberry Pi Foundation plans to foster its mission of promoting the $35 SBC as a tool to teach children computer skills and encourage inventiveness.

This month’s issue offers many other interesting reads. For example, columnist Jeff Bachiochi continues his series on creating user-friendly graphic displays. Part 1 focused on the microcontroller used to create his serial display. Part 2 discusses implementing dynamic button commands (p. 70).

In Part 4 of his “Testing and Testability” series (p. 52), columnist George Novacek explains the importance of an electronic system’s internal diagnostics. In addition, columnist Bob Japenga wraps up his “Concurrency in Embedded Systems” series by focusing on file usage (p. 48). “Modern embedded systems are doing more than I ever imagined when I first started,” Japenga says. “Adding a file system to your design can provide significant advantages to improve your product.”

This issue also presents two more final installments. One describes how to use a DSP-SQL interface to access large amounts of data (p. 20). The other outlines a DIY SBC project (p. 30).


Editor’s Note: The Client Profile focusing on Beta LAYOUT in Circuit Cellar’s June issue (p. 16) included incorrect information. Tony Shoot can be reached at tony@beta-layout.us. Visit circuitcellar.com/featured/client-profile-beta-layouts online to see the full profile.

CC 277: (Re)Discovering Embedded

Authors in this issue range from a columnist who reintroduces us to the advantages of switched-capacitor filters to a frequent contributor who discusses his first encounter—and project—with the credit card-sized Raspberry Pi computer.

Columnist Robert Lacoste recently rediscovered one of his 1981 Elektor magazines, which included an article on switched-capacitor filters. “Since mastering switched-capacitor filters is now mandatory for many mixed-signal designs, I thought: Why not refresh the topic for a Circuit Cellar Darker Side article?” Lacoste says. Beginning on page 56, Lacoste shows you how to modify a simple one-pole RC filter into a switched-capacitor filter.

Frequent contributor Brian Millier placed his name on a waiting list to purchase his first Raspberry Pi. He finally received it in late 2012 and started the project that would inspire his two-part series “Raspberry Pi I/O?Board” (p. 42). The series explores the strengths and weaknesses of the single-board computer (SBC)?and explains the versatile I/O board he developed for it. “In the time since I received my Raspberry Pi, one of the board’s developers has designed an I/O board called the Gertboard. I feel my board is quite distinct and has some advantages over the Gertboard,” Millier says.

Speaking of the Raspberry Pi’s developers, this issue includes an interview with “RPi hardware guy” Peter Lomas (p. 38). He looks at the growth in popularity of the Raspberry Pi since its initial launch and shares how the nonprofit Raspberry Pi Foundation plans to foster its mission of promoting the $35 SBC as a tool to teach children computer skills and encourage inventiveness.

This month’s issue offers many other interesting reads. For example, columnist Jeff Bachiochi continues his series on creating user-friendly graphic displays. Part 1 focused on the microcontroller used to create his serial display. Part 2 discusses implementing dynamic button commands (p. 70).

In Part 4 of his “Testing and Testability” series (p. 52), columnist George Novacek explains the importance of an electronic system’s internal diagnostics. In addition, columnist Bob Japenga wraps up his “Concurrency in Embedded Systems” series by focusing on file usage (p. 48). “Modern embedded systems are doing more than I ever imagined when I first started,” Japenga says. “Adding a file system to your design can provide significant advantages to improve your product.”

This issue also presents two more final installments. One describes how to use a DSP-SQL interface to access large amounts of data (p. 20). The other outlines a DIY SBC project (p. 30).


Editor’s Note: The Client Profile focusing on Beta LAYOUT in Circuit Cellar’s June issue (p. 16) included incorrect information. Tony Shoot can be reached at tony@beta-layout.us. Visit circuitcellar.com/featured/client-profile-beta-layouts online to see the full profile.