SG1577SZ Application Field and Working Principle

PMIC - Voltage Regulators - DC DC Switching Controllers

SG1577SZ from STMicroelectronics is a high-performance voltage regulator IC designed for automotive applications and featuring low quiescent current and high accuracy. The working principle and application field of SG1577SZ is discussed in this article.

Working Principle

The SG1577SZ is a dual-channel synchronous step-down DC/DC current mode controller featuring a voltage mode control loop to ensure a fast transient response and very low output ripple. The controller includes an adaptive error amplifier that minimizes the output voltage ripple, an integrated active-high gate driver with bootstrap diode, and an integrated high-side power MOSFET with a Gate On-Resistance (GOR) guarantee.

The SG1577SZ has two independent outputs: one is a high-side buck controller supporting up to 6A output current and the other one is a low-side buck output supporting up to 4A output current. Both outputs feature a soft-start / fast-shrink current limit and are fully protected against over-voltage, under-voltage, over-temperature, and over-current. To speed up the current limit setting process, the SG1577SZ includes an OVP delay timer that can be programmed to delay the OVP assertion until the output voltage reaches a predetermined threshold.

The SG1577SZ integrates a voltage mode control loop to ensure fast transient response and very low output ripple. The controller also includes an adaptive error amplifier, a peak current limit circuitry with adjustment slope, a low-side power MOSFET driver with a reverse-current protection circuit, and a built-in high-side power MOSFET. Furthermore, the SG1577SZ also features a low-side current monitor with adjustable slew-rate limit, a high-side current monitor with adjustable slew-rate limit, and an adjustable low-side output voltage generator.

Application Field

SG1577SZ is suitable for applications such as automotive DC-DC converters, non-isolated DC-DC converters, and also in portable power storage systems and power distribution systems. It can be used in automotive infotainment systems, body lighting systems, power management systems, battery management systems, power supplies, and UPS systems.

The SG1577SZ is ideal for applications that require high efficiency, small size and low power consumption. It is also suitable for applications requiring high current and low output voltage ripple. Its adaptive error amplifier can minimize the output voltage ripple, and its integrated active-high gate driver with bootstrap diode ensures fast switching.

The SG1577SZ is also suitable for applications that require a high accuracy and low quiescent current. Its integrated high-side power MOSFET and Gate On-Resistance guarantee ensures a low quiescent current and an accurate output voltage. Furthermore, its low-side current monitor can be used to fine-tune the output current.

Conclusion

The SG1577SZ from STMicroelectronics is a high-performance dual-channel synchronous step-down DC/DC current mode regulator featuring a voltage mode control loop that ensures a fast transient response and very low output ripple. It is suitable for a wide range of applications such as automotive DC-DC converters, non-isolated DC-DC converters and power storage systems. Its integrated high-side power MOSFET with Gate On-Resistance guarantee ensures a low quiescent current and accurate output voltage. The controller is protected against a variety of fault conditions and features a low-side current monitor with adjustable slew-rate limit, a high-side current monitor with adjustable slew-rate limit, and an adjustable low-side output voltage generator.