Monolithic Power Systems Inc. MPQ4590GS-P

Overview

MPQ4590GS-P from Monolithic Power Systems is a 640V primary-side constant-voltage (CV) regulator with integrated 640V/13.5Ω MOSFET, supporting buck/buck-boost/boost/flyback topologies in non-isolated power supplies. It delivers up to 400mA output current in CCM mode, achieves <30mW no-load consumption, and operates across –40°C to +125°C for automotive PTC heaters and industrial standby power.

For engineers reviewing the MPQ4590GS-P datasheet, MPQ4590GS-P pinout, MPQ4590GS-P application, or MPQ4590GS-P equivalent, this device enables optocoupler-free CV regulation in AEC-Q100-qualified low-power AC/DC converters where light-load efficiency, thermal robustness, and topology flexibility are critical selection criteria.

Technical Context

The MPQ4590GS-P implements green-mode operation via frequency foldback and peak-current compression: switching frequency and peak current both decrease under light load to maintain high efficiency down to no-load conditions. Its internal error amplifier samples FB voltage 6µs after MOSFET turn-off and regulates against a 2.55V reference.

Protection logic integrates OTP (150°C shutdown, 30°C hysteresis), UVLO (5.3V turn-on / 5.6V turn-off), OLP (1.7V FB threshold, 220ms delay), SCP (900mA typical threshold), and open-loop detection (0.5V FB threshold). Leading-edge blanking (350ns on DRAIN, 180ns for SCP) suppresses false triggering from parasitic spikes.

Key Specifications

Pinout & Package

MPQ4590GS-P is housed in a standard SOIC-8 package with exposed thermal pad connected to DRAIN pin for enhanced heat dissipation. Pin 1 (VCC) supplies control circuitry; Pin 2 (FB) senses output voltage via resistive divider; Pins 3/5/6/8 are NC; Pin 4 (SOURCE) serves as ground reference for VCC and FB; Pin 7 (DRAIN) connects to high-voltage input and internal MOSFET drain.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side CV regulator applications.

Compared with MPQ4570GS-P, MPQ4590GS-P adds 140V headroom and automotive qualification; compared with UCC2891DR, it reduces component count and improves light-load efficiency by integrating the HV MOSFET and enabling adaptive frequency control.

Availability

MPQ4590GS-P is available at Aetrix Electronics and suitable for automotive PTC heater control, industrial standby power supplies, home appliance auxiliary rails, and smart meter power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MPQ4590GS-P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance power management ICs, with design centers in the US, China, and Taiwan and global manufacturing partnerships.

The MPQ4590 product line targets cost-sensitive, space-constrained non-isolated AC/DC converters requiring optocoupler-free regulation, high reliability, and AEC-Q100 compliance for automotive and industrial edge applications.

FAQ

What topologies does MPQ4590GS-P support?

The MPQ4590GS-P supports buck, buck-boost, boost, and flyback topologies. Its primary-side regulation architecture eliminates the need for optocouplers or secondary-side feedback components in all four configurations. The integrated 640V MOSFET enables direct high-voltage connection in buck and boost modes, while flyback operation provides isolation capability with indirect feedback through the transformer auxiliary winding.

How does MPQ4590GS-P achieve <30mW no-load consumption?

MPQ4590GS-P achieves ultra-low no-load consumption through coordinated green-mode techniques: frequency foldback reduces switching losses, while peak-current compression lowers conduction losses. As load decreases, both switching frequency and peak current scale down, minimizing total power dissipation. Internal VCC regulation and low ICC (200μA in no-switching mode) further contribute to sub-30mW performance.

What is the role of the NC pins (3, 5, 6, 8) in SOIC-8 layout?

Pins 3, 5, 6, and 8 are internally unconnected and must remain floating-no trace, pad, or copper pour should contact them. This prevents unintended coupling, noise injection, or thermal stress. The datasheet explicitly prohibits routing signals or grounding these pins, as doing so may disrupt internal biasing or cause latch-up under transient conditions.

Can MPQ4590GS-P be used in isolated flyback designs?

Yes, MPQ4590GS-P supports isolated flyback operation using indirect feedback via an auxiliary winding on the transformer. The FB pin monitors reflected voltage rather than direct output voltage, enabling regulation without optocoupler or secondary-side components. Designers must size the auxiliary winding turns ratio to ensure FB voltage remains within 0.4–2.65V across all operating conditions.

What is the minimum off-time limit and how does it affect power output?

The MPQ4590GS-P has a minimum off-time limit of 12μs (typical) that directly constrains maximum output power. In CCM, power scales with inductance and τ_minoff: P_max ≈ V_O × (V_O / (2L)) × τ_minoff. A smaller inductor increases ripple current but risks exceeding peak-current limits; larger inductors improve regulation but raise OLP trip points. For 12V/300mA, ≥0.36mH is recommended.

How does open-loop protection trigger and recover?

Open-loop protection triggers when FB voltage falls below 0.5V (typical), indicating loss of feedback path or output short. The IC stops switching and initiates automatic restart after discharging VCC to 2.4V. Recovery requires VCC to recharge above 5.3V via the internal HV regulator, followed by soft-start sequence. During initial startup, open-loop detection is blanked to avoid false triggering.

Is external VCC supply supported and when is it beneficial?

Yes-an auxiliary VCC supply derived from the output via resistor divider (R3) and Zener diode (D3) is supported for outputs >7V. This bypasses the internal HV regulator, reducing no-load consumption further. It is beneficial in applications demanding <15mW no-load draw or where VCC capacitor self-discharge causes premature shutdown during extended standby.