Contactless IC Power Supply Circuit Reducing UHF Losses
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Solution Overview
Problem
Conventional methods for generating a DC supply voltage from UHF antenna signals in contactless integrated circuits suffer from inefficiencies due to high frequency electrical losses and suboptimal signal conditions, resulting in lower than expected voltage output.
Innovation Solution
A power supply circuit that includes a primary rectifier circuit for producing a primary DC voltage, a low voltage oscillator to generate optimized pump signals, and a charge pump driven by these signals to boost the voltage efficiently, reducing UHF losses and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If antenna signals at UHF frequency are applied directly to a charge pump, then the charge pump can operate with the available signals, but electrical losses increase due to high frequency parasitic capacitances
Solution Approach 1:
The power supply circuit is divided into two independent parts: a rectification stage that converts UHF antenna signals to DC voltage, and a charge pump stage that uses this DC voltage to generate boosted voltages. This segmentation allows each stage to operate at its optimal frequency, with the rectifier handling the high frequency UHF signals and the charge pump operating at lower frequencies to minimize parasitic losses.
Solution Approach 2:
A rectification circuit is introduced as an intermediary between the UHF antenna signals and the charge pump. This rectifier converts the high frequency AC antenna signals into DC voltage, which then serves as the input to the charge pump. This intermediary transformation eliminates the direct application of high frequency signals to the charge pump, thereby reducing electrical losses from parasitic capacitances.
2Device complexity
If antenna signals are used directly to drive the charge pump, then no additional rectification circuit is needed, but the conversion efficiency is degraded due to suboptimal signal conditions
Solution Approach 1:
The rectification circuit performs preliminary conversion of the UHF antenna signals into DC voltage before the charge pump operates. This preliminary action prepares the signal in the optimal form (DC voltage) for the charge pump to function efficiently, ensuring maximum conversion efficiency while maintaining a relatively simple overall circuit structure.
3Device complexity
If UHF antenna signals are applied to the charge pump, then the circuit can be simplified, but the voltage output is lower than expected due to signal overlap and phase issues
Solution Approach 1:
The direct electrical connection between antenna signals and charge pump is replaced by an electrical energy conversion process through rectification. Instead of applying AC signals directly to the charge pump electrodes, the system converts UHF electromagnetic energy to DC electrical energy first, then uses this DC voltage to drive the charge pump, resulting in superior voltage output.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution achieves a higher efficiency of 5 to 25% compared to conventional charge pumps, enabling a more effective conversion of antenna signals into usable DC voltage with reduced electrical losses.
Implementation Method 1
In the presence of an electric field E located in the UHF band, emitted for example by a contactless integrated circuit reader RD1, antenna signals S1, S2 appear in conductors W1, W2
Implementation Method 2
The circuit comprises a primary rectifier circuit PRCT supplying a primary DC voltage Vccp from the antenna signals S1, S2 or from one of these signals
Implementation Method 3
The charge pump PMP2 is driven by the pumping signals H1, H2 and supplies the DC voltage Vcc by boosting the primary voltage Vccp
Data Source
Figure 1~4
Figure 5~7B
Figure 8~9
AI summary
The method involves producing a direct voltage (Vccp) equal to a fraction of a supply voltage (Vcc) from high frequency antenna signals (S1, S2). Pumping signals (H1, H2) having a frequency lesser than the frequency of the antenna signals are produced using a low voltage oscillator (LVOSC) electrically supplied by the voltage (Vccp). The voltage (Vccp) is boosted using a charging pump (PMP2) driven by the signals (H1, H2) for obtaining the supply voltage. Independent claims are also included for the following: (1) an integrated circuit comprising an electronic circuit (2) an electronic circuit comprising a control unit (3) a portable electronic object comprising an integrated circuit.