Mobile phone Circuits to Get Even smaller

Transceivers, appliances such as mobile phones that can send and receive messages, have become smaller and smaller over the last few years, but users are about to experience a new meaning in miniaturisation. 

Research at The Hong Kong University of Science & Technology (HKUST) has successfully combined a unique system architecture and new circuit design techniques to reduce them in size like never before. 

Principal Investigator Dr Howard Luong said the handset of a typical mobile phone today may contain between 150 and 300 separate electrical components.

His research group proposed and demonstrated circuit techniques that make it possible to combine many of these components to a single chip and therefore to significantly reduce the size of circuitry (see example in graphic). A US patent has been granted for one of the circuit techniques. 
 
The transformation applies to the CMOS (Complimentary Metal-Oxide Semiconductor) manufacturing process, which can produce integrated circuits and systems with the highest integration level at the lowest cost. Applying new techniques to the CMOS process, Dr Luong’s research enables many “off-chip” components to be combined to realize a system-on-chip. “But,” he said, “this integration created great challenges in circuit implementation.” Part of the research was to solve the problems by new circuit design techniques.
 
“The system architecture and circuitry go hand in hand, he added. “They must both work, or neither will be useful.”
The resulting design gives the highest component integration in the smallest chip area ever reported, said Dr Luong.
In his design, all off-chip components are fitted into a central chip measuring 36 mm with packaging, and 8mm without being packaged.
Dr Luong’s miniaturisation method means appliances will soon be made for even lower cost and lower power consumption in addition to being much smaller in size and lighter in weight.
“With the lowering of cost, size and power, many new and interesting applications will become possible and practical,” he said.
Low-power wireless transceivers, for example, could be integrated into implanted devices such as heart pacemakers to wirelessly transmit and receive information between patients and doctors or monitoring systems.
Wearable mobile phones as small as wrist watches at an affordable price could also become a reality.

Auther

Principal Investigator

Dr Howard Luong

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Simple Telephone Record Control

This circuit will allow you to connect any tape recorder that has a mic and remote input to a phone line and automatically record both sides of a conversation when ever the phone is in use. You will need to take a couple of voltage readings before connecting the circuit. First determine the polarity of your phone line and connect it to the circuit as shown and then determine the polarity of the remote input and connect it to the circuit. Circuit operation is as follows. When the phone is on hook the voltage across the phone line is about 48volts dc. When the phone is off hook the voltage will drop to below 10volts dc. When the line voltage is at 48volts the FET is off which causes Q2 and Q3 to be off. When the phone is picked up the FET turns on along with Q2 and Q3 which turns your recorder on. The tape recorder must be in the record mode at all times. As you can see the power source for the circuit is the phone line.

Circuit Diagram

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Simple Telephone Amplifier Circuit Diagram

The output telephone signal is more powerful then the signal fed to base of the transistor T₁. The output signal from transistor T₁ is fed to pin no 3 of power amplifier LM386 which amplify up to necessity level and output is obtained from pin no 5 is fed to speaker through capacitor C₉. The V_CC is given to IC₁ through pin 6. The telephone signal is fed in to circuit through two ways.

1. Direct supply telephone signal from telephone line to the point where coil L₁ is connected as shown in figure 2.
2. Or connect this peak up coil L₁ and so adjusted near telephone set where excellent voice be able to single out. 

Simple Telephone Amplifier Circuit Diagram

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R₁ = 100 KΩ

R₂ = 39 KΩ

R₃ = 2.2 KΩ

R₄ = 680 Ω

R₅ = 100 Ω

VR₁ = 4.7 KΩ

VR₂ = 10 KΩ

Capacitors

C₁ = 27 KPF (273)

C₂, C₄ = 2.2 µF/16 V

C₃ = 22 µF/16 V

C₅, C₁₀ = 100 µF/16 V

C₆ = 10 µF/16 V

C₇ = 100 KPF (104)

C₈ = 47 KPF (473)

C₉ = 220 µF/16 V

Semiconductors

T₁ = BC147B

IC₁ = LM386 power amplifier

Miscellaneous

L₁ = Pick up Coil

Speaker 8Ω

SW₁ = On/Off switch

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