Power Stage (H-Bridge) for Servo Drives

Product Specifications

Technical details and manufacturing context for Power Stage (H-Bridge)

Definition

The power stage, specifically implemented as an H-bridge circuit, is a critical component of a servo drive amplifier. It functions as the final power conversion stage, receiving low-power control signals from the drive's controller and amplifying them to deliver high-current, bidirectional power to the servo motor. By rapidly switching its four power transistors (or other switching elements) in specific patterns, it precisely controls both the magnitude and direction of current flowing through the motor windings, enabling accurate torque, speed, and position control. This component is typically used in industrial automation, robotics, and CNC machinery where precise motion control is required. The H-bridge topology allows for four-quadrant operation, meaning the motor can be driven in both directions and can also regenerate energy back to the supply during deceleration. The power stage is designed to handle continuous output currents from 10 to 50 A and peak currents from 20 to 100 A, depending on the model. It operates from a DC supply voltage of 24 to 80 V and switches at frequencies between 8 and 20 kHz, which affects audible noise and efficiency. The efficiency at rated load is typically 95 to 98%. The operating temperature range is -40 to 85 °C, with storage from -40 to 105 °C. The unit is protected against dust and water according to IP54 to IP65 (IEC 60529). Isolation voltage between power and control circuits is 1500 to 2500 V AC (IEC 61800-5-1). Thermal resistance from junction to case is 0.5 to 1.5 K/W. The weight ranges from 0.5 to 2.0 kg, and dimensions vary from 100×60×30 mm to 200×120×60 mm. Materials used include Silicon Carbide (SiC) MOSFETs, IGBTs, gate driver ICs, direct bonded copper (DBC) substrates, aluminum oxide or aluminum nitride ceramics, copper busbars, and polyimide or epoxy insulation. These materials are selected for high thermal conductivity, electrical isolation, and mechanical robustness. The power stage is a component that must be integrated into a complete servo drive system; it is not a standalone product. For specific applications, the actual values must be confirmed with the legal manufacturer or supplier.

Working Principle

The H-bridge consists of four switching elements (typically MOSFETs or IGBTs) arranged in an 'H' configuration with the motor connected between the two legs. By turning on the diagonal pairs of switches (e.g., top-left and bottom-right), current flows through the motor in one direction. Switching to the opposite diagonal pair (top-right and bottom-left) reverses the current flow, changing the motor's rotational direction. Pulse-width modulation (PWM) applied to these switches controls the average voltage and current supplied to the motor, regulating its torque and speed. Sophisticated gate drive circuits ensure fast, precise switching while preventing shoot-through (simultaneous conduction of both switches on one leg).

Common Materials

Silicon Carbide (SiC) MOSFETs, Insulated-Gate Bipolar Transistors (IGBTs), Gate Driver ICs, Direct Bonded Copper (DBC) Substrate, Aluminum Oxide or Aluminum Nitride Ceramic, Copper Busbars, Polyimide or Epoxy Insulation

Technical Parameters

Parameter	Typical range	Notes & selection driver
DC Supply Voltage	24–80 V DC	Determines motor voltage and speed range.
Continuous Output Current	10–50 A	Thermal limit for continuous operation.
Peak Output Current	20–100 A	For acceleration and high torque demands.
Switching Frequency	8–20 kHz	Affects audible noise and efficiency.
Efficiency	95–98 %	At rated load and nominal voltage.
Operating Temperature	-40–85 °C	Ambient temperature range.
Storage Temperature	-40–105 °C	Non-operating condition.
Ingress Protection	IP54–IP65	Protection against dust and water.IEC 60529
Isolation Voltage	1500–2500 V AC	Between power and control circuits.IEC 61800-5-1
Thermal Resistance (Junction to Case)	0.5–1.5 K/W	Lower is better for heat dissipation.
Weight	0.5–2.0 kg	Depends on current rating and heatsink.
Dimensions (L × W × H)	100×60×30–200×120×60 mm	Envelope size for integration.

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Power Semiconductor Switches
Perform the high-current switching to control motor current flow. Arranged in the H-bridge topology.

Material: Silicon or Silicon Carbide semiconductor
Gate Driver Circuit
Amplifies low-power control signals to the voltage/current levels required to rapidly and reliably turn the power switches on and off.

Material: Integrated Circuit (IC), discrete transistors, resistors, capacitors
DC Bus Capacitors Part
Provide local energy storage on the DC bus to supply instantaneous current demands and filter voltage ripple.

Material: Aluminum electrolytic or film capacitors
Current Sensors
Measure the phase current(s) being delivered to the motor for closed-loop control and protection.

Material: Shunt resistor, Hall-effect sensor, or current transformer core
Heat Sink Part
Dissipates heat generated by the power semiconductors and other components to maintain safe operating temperatures.

Material: Aluminum alloy with anodized surface

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Servo Drive Amplifier

View system integration details

Manufacturers of Power Stage (H-Bridge)

Manufacturer profiles associated with Power Stage (H-Bridge).

Sourcing Power Stage (H-Bridge) from China?

Tell us your specification and target quantity — we will match it against manufacturer records and come back with the factories that fit.

Request manufacturers We manufacture this

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review · Page last updated 6 September 2026

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Frequently Asked Questions

What is the role of the power stage in a servo drive?

The power stage is the final conversion stage that amplifies low-power control signals to high-current, bidirectional power for the servo motor. It controls the magnitude and direction of motor current, enabling precise torque, speed, and position control.

What are the typical voltage and current ranges for this power stage?

The DC supply voltage range is 24–80 V. Continuous output current is 10–50 A, and peak output current is 20–100 A. These values are reference ranges; actual ratings depend on the specific model and must be confirmed with the manufacturer.

What materials are used in the construction of this H-bridge power stage?

Common materials include Silicon Carbide (SiC) MOSFETs, IGBTs, gate driver ICs, direct bonded copper (DBC) substrates, aluminum oxide or aluminum nitride ceramics, copper busbars, and polyimide or epoxy insulation. These are selected for thermal performance and electrical isolation.

How does the H-bridge control motor direction and speed?

By switching diagonal pairs of transistors, the direction of current through the motor is reversed, changing rotation direction. Pulse-width modulation (PWM) adjusts the average voltage and current, thereby controlling speed and torque. Gate drive circuits ensure precise switching and prevent shoot-through.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Buyer enquiry

Request manufacturing insight for Power Stage (H-Bridge)

Ask for use case, specification boundaries, supplier type, and RFQ preparation information for this product.

Where it goes: Straight to the CNFX editorial desk, and to the manufacturer if this product is linked to a claimed profile. Nothing is broadcast to a supplier list.
Your details stay here: We do not sell or rent enquiry data, and we do not add you to a mailing list. Used only to answer this request.
No commission, no middleman: CNFX is a directory. We take no cut of any order and never negotiate on a supplier's behalf.
What we don't claim: A listing is not an endorsement. Qualify every supplier and verify every figure yourself before ordering.

current:	Continuous current rating up to 100A, peak current up to 200A (depends on cooling)
voltage:	Up to 600V DC bus voltage
temperature:	-40°C to +125°C (operating), -55°C to +150°C (storage)
isolation voltage:	2500Vrms (input to output)
switching frequency:	Up to 20kHz (PWM frequency)

Power Stage (H-Bridge)

Product Specifications

Applied To / Applications

Industrial Ecosystem & Supply Chain Structure

Application Fit & Sizing Matrix

Reliability & Engineering Risk Analysis

Compliance & Manufacturing Standards