H-Bridge Driving Circuit Standby Mode Control

Solution Overview

Problem

Existing driving circuits face challenges in implementing a standby mode without increasing the number of pins, particularly in compact ICs where pin count is limited, leading to difficulties in power consumption management.

Innovation Solution

A driving circuit design that utilizes one or two control input pins to switch between multiple states and a standby mode by maintaining a predetermined state for a specific judgment period, allowing for power-saving without additional pins, and distinguishes between intended transitions and high-impedance states through PWM frequency settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If an enable pin is added to support standby mode, then power consumption management is improved, but the number of pins increases

Engineering Contradiction:

Improvepower consumptionVSAvoidnumber of pins

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control input pins are designed to serve dual purposes: they control the H-bridge circuit states during normal operation and simultaneously function as standby mode control inputs. By monitoring whether control input pins maintain a predetermined state for a predetermined period, the circuit automatically enters standby mode without requiring a separate enable pin, thus achieving multi-functionality with existing pins.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If the number of pins is reduced for compact IC design, then device size is improved, but the ability to implement standby mode deteriorates

Engineering Contradiction:

Improvenumber of pinsVSAvoidstandby mode implementation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The control input pins are designed to serve dual purposes: they control the H-bridge circuit states during normal operation and simultaneously function as standby mode control inputs. By monitoring whether control input pins maintain a predetermined state for a predetermined period, the circuit automatically enters standby mode without requiring a separate enable pin, thus achieving multi-functionality with existing pins.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If control input signals are monitored for standby mode detection, then power consumption management is improved, but the complexity of control logic increases

Engineering Contradiction:

Improvepower consumptionVSAvoidcontrol logic

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The logic circuit continuously monitors the control input pins and maintains a predetermined state for a predetermined period before triggering standby mode. This preliminary monitoring action allows the circuit to distinguish between temporary control signals and genuine standby requests, implementing power management through existing control logic without requiring additional complex detection circuits.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10992244B2Load driving circuit

Publication Date: 2021.04.27 ROHM CO LTD

AI summary

Two control input pins INA and INB receive two control input signals from an external circuit. A logic circuit generates an internal signal SINT for indicating the state of an H-bridge circuit according to the two control input signals INA and INB. A pre-driver drives the H-bridge circuit based on the internal signal SINT. When the two control input signals INA and INB continue in a predetermined state for a predetermined judgment period of time, a standby circuit switches a driving circuit to a standby mode.