Driving Apparatus Dynamic Reference Voltage for Low Current Detection

Solution Overview

Problem

Conventional driving apparatuses face challenges in accurately detecting output current at low current set values, leading to waveform disturbances and reduced motor control accuracy due to the limitations in detecting voltage differences between the detected voltage and reference voltage.

Innovation Solution

The driving apparatus incorporates a current output unit with switchable ON resistances, allowing for the use of different reference voltages in large and small current time periods, enabling the comparator to accurately compare detected voltages and control output current, thereby improving detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the current set value is lowered to reduce motor current, then energy consumption is reduced, but the comparator fails to accurately detect the output current due to insufficient voltage difference

Engineering Contradiction:

Improvemotor energy consumptionVSAvoidoutput current detection accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent changes the reference voltage parameter dynamically based on the current set value. When the current set value is low, the reference voltage is also lowered proportionally, maintaining a sufficient voltage difference for accurate comparator detection. This allows the system to operate at low currents while preserving measurement accuracy.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The reference voltage is made dynamic rather than fixed. The system automatically adjusts the reference voltage level according to the current operating conditions, specifically lowering it when the current set value is low to ensure the comparator can still detect small voltage differences accurately.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the detected voltage and reference voltage are both lowered at low current set values, then the comparator can maintain detection capability, but the voltage difference becomes too small for accurate comparison

Engineering Contradiction:

Improvecomparator detection capabilityVSAvoidvoltage difference detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts the reference voltage parameter to maintain an optimal voltage difference for comparator operation. By changing the reference voltage in proportion to the current set value, the system ensures that the voltage difference remains sufficient for accurate detection even at low current levels.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from the current set value to automatically adjust the reference voltage level. This feedback mechanism ensures that the reference voltage is always appropriately scaled to maintain accurate comparison capability across different operating conditions.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If the output current waveform is disturbed due to poor detection accuracy, then motor control precision deteriorates, but increasing the current set value improves detection accuracy

Engineering Contradiction:

Improveoutput current detection accuracyVSAvoidmotor current consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the reference voltage parameter dynamically based on the current set value. When the current set value is low, the reference voltage is also lowered proportionally, maintaining a sufficient voltage difference for accurate comparator detection. This allows the system to operate at low currents while preserving measurement accuracy.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The reference voltage is made dynamic rather than fixed. The system automatically adjusts the reference voltage level according to the current operating conditions, specifically lowering it when the current set value is low to ensure the comparator can still detect small voltage differences accurately.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11139809B2Driving apparatus

Publication Date: 2021.10.05 KK TOSHIBA

AI summary

A driving apparatus includes a current output unit, a reference voltage output unit, a comparator, and a drive control unit. The current output unit is switchable to either a first ON resistance or a second ON resistance that is N times (N>1) the first ON resistance. The reference voltage output unit outputs a fist reference voltage during a large current time period, and outputs a second reference voltage that is M times (M>1) the first reference voltage during a small current time period. The drive control unit performs control to perform switching to the first ON resistance during the large current time period, and to perform switching to the second ON resistance during the small current time period.