1. An arrangement for saving energy in a radio device transmitter, radio frequency amplifiers of which being at least a VGA and a power amplifier, which VGA comprises at least one main differential pair, total current of which being arranged to be dependent on input signal of the VGA and a collector current of one transistor of the main differential pair being output signal of the VGA, the VGA further comprising a control circuit to change mutual steering of transistors in the main differential pair so that VGA’s current gain changes corresponding to changes in a gain control signal, the arrangement comprising in the VGA a bias current source controllable by said gain control signal, output of which bias current source being connected to said power amplifier to make a steady current of the power amplifier dependent on the current gain and thus transmitting power, wherein;
said bias current source comprises a bias differential pair, the bases of the transistors of which are connected parallel to the bases of the transistors of the main differential pair for steering these pairs by one and the same control signal, and a current of said output of the bias current source is arranged to track in proportion collector current of the transistor of the bias current source, the base of which is parallel with the base of said one transistor of the main differential pair.
2. The arrangement according to claim 1, the bias differential pair and the main differential pair being located on one and the same substrate to equalize the electric characteristics of these pairs.
3. The arrangement according to claim 1, output current of the bias current source being arranged to track in proportion the collector current of the transistor of the bias differential pair by means of a current mirror circuit, a transistor of which is load of said transistor of the bias differential pair and a current of another transistor of the current mirror circuit is output current of the bias current source.
4. The arrangement according to claim 1, the steady current of the power amplifier being arranged to track in proportion the output current of the bias current source by means of a second current mirror circuit, a transistor of which is load of said output of the bias current source and a current of another transistor of the second current mirror circuit is the steady current of the power amplifier.
5. The arrangement according to claim 4, said second current mirror being asymmetric so that the output current of the bias current source is substantially lower than the steady current of the power amplifier to reduce the own losses of the bias current source.
6. The arrangement according to claim 1, the radio device transmitter further comprising a driver amplifier for said power amplifier, wherein;
the bias current source further has a second output, a current of which is arranged to track in proportion the collector current of the transistor of the bias differential pair, the base of which is parallel with the base of said one transistor of the main differential pair, which second output is connected to said driver amplifier to make a steady current of the driver amplifier dependent on the current gain and thus transmitting power.
7. The arrangement according to claim 1, the control circuit of the VGA having a differential output, wherein;
the VGA comprises first and second main differential pairs being parallel such that the bases of first transistors of these pairs are connected to first terminal of the differential output of the control circuit and the bases of second transistors of these pairs are connected to second terminal of the differential output of the control circuit, and said input signal is arranged to be fed to a third differential pair, the collector of first transistor of the third pair being connected to the emitters of the transistors of the first pair and the collector of second transistor of the third pair being connected to the emitters of the transistors of the second pair.
8. A radio device having an arrangement for saving energy in it’s transmitter, radio frequency amplifiers of which being at least a VGA and a power amplifier, which VGA comprises at least one main differential pair, total current of which being arranged to be dependent on input signal of the VGA and a collector current of one transistor of which being output signal of the VGA, the VGA further comprising a control circuit to change mutual steering of transistors in the main differential pair so that VGA’s current gain changes corresponding to changes in gain control signal, the arrangement comprising in the VGA a bias current source controllable by said gain control signal, output of which bias current source being connected to said power amplifier to make a steady current of the power amplifier dependent on the current gain and thus transmitting power, wherein;
said bias current source comprises a bias differential pair, the bases of the transistors of which are connected parallel to the bases of the transistors of the main differential pair for steering these pairs by one and the same control signal, and a current of said output of the bias current source is arranged to track in proportion collector current of the transistor of the bias differential pair, the base of which is parallel with the base of said one transistor of the main differential pair.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for manufacturing a keypad which includes a plurality of keys, the method comprising the steps of:
(1) forming a key body of a light-transmissive resin material;
(2) coating a high-hardness transparent coating layer onto a surface of the key body in order to increase hardness;
(3) coating a key background color paint layer for color presentation onto a lower surface of the key body;
(4) coating a light-shielding paint layer onto a lower surface of the key background color paint layer in order to prevent light from being transmitted through a portion other than a light-transmissive marking portion;
(5) forming the light-transmissive marking portion by performing a laser processing according to a shape of a numeral, a character, or a symbol with respect to the lower surface of the key body so as to remove the key background color paint layer and the light-shielding paint layer;
(6) forming a metallic vacuum deposition layer on the lower surface of the key body and a lower surface of the light-shielding paint layer; and
(7) attaching a one of color-printed layer and a cellophane paper to a lower surface of the metallic vacuum deposition layer so as to present various colors.
2. The method as claimed in claim 1, wherein step (2) is omitted by forming the key body from a high-hardness light-transmissive resin material which contains additives for reinforcing hardness and a lubrication property and thus improving abrasion resistance and scratch resistance properties of the key body.
3. The method as claimed in claim 1, wherein, in step (7), the cellophane paper is attached to a surface of an elastic pad for the keypad, or a surface of the elastic pad is color-printed.
4. The method as claimed in claim 1, wherein the light-transmissive resin material includes one of polycarbonate, acrylic resin, and polyethylene terephthalate (PET).
5. The method as claimed in claim 1, wherein the metallic vacuum deposition layer is made of any one selected from a group consisting of aluminum (Al), chromium (Cr), Nickel (Ni), tin (Sn) and titanium (Ti).
6. The method as claimed in claim 1, wherein the metallic vacuum deposition layer is made of any one selected from a group consisting of silicon dioxide (SiO2), titanium dioxide (TiO2), and zirconium dioxide (ZrO2).
7. The method as claimed in claim 1, wherein the resin material is one of transparent and translucent.
8. The method as claimed in claim 1, wherein the light-shielding paint layer is opaque.
9. The method as claimed in claim 1, wherein the marking portion is one of transparent and translucent.
10. A keypad for a mobile phone including a plurality of keys, each key includes a key body of a light-transmissive resin material and a high-hardness transparent coating layer coated onto a surface of the key body in order to increase hardness, the key comprising:
a key background color paint layer for color presentation, coated onto a lower surface of the key body;
a light-shielding paint layer coated onto a lower surface of the key background color paint layer;
a light-transmissive marking portion formed by performing a laser processing according to a shape of a numeral, a character, or a symbol with respect to the lower surface of the key body so as to remove the key background color paint layer and the paint layer;
a metallic vacuum deposition layer formed on the lower surface of the key body and a lower surface of the paint layer; and
a color-printed layer or a cellophane paper attached to a lower surface of the metallic vacuum deposition layer so as to present various colors.
11. The keypad as claimed in claim 10, wherein the resin material includes a high-hardness resin material which contains additives for reinforcing hardness and a lubrication property so as to improve abrasion resistance and scratch resistance properties of the key body.
12. The keypad as claimed in claim 10, wherein the resin material includes one of polycarbonate, acrylic resin, and polyethylene terephthalate (PET).
13. The keypad as claimed in claim 10, wherein the metallic vacuum deposition layer is made of any one selected from a group consisting of aluminum (Al), chromium (Cr), Nickel (Ni), tin (Sn), and titanium (Ti).
14. The keypad as claimed in claim 10, wherein the metallic vacuum deposition layer is made of any one selected from a group consisting of silicon dioxide (SiO2), titanium dioxide (TiO2), and zirconium dioxide (ZrO2).
15. The method as claimed in claim 10, wherein the resin material is one of transparent and translucent.
16. The Method as claimed in claim 10, wherein the paint layer is opaque.
17. The method as claimed in claim 10, wherein the marking portion is one of transparent and translucent.
18. A keypad for a mobile phone including a plurality of keys, each key comprising:
a key body made of a transparent resin material;
a high-hardness transparent coating layer coated onto a surface of the key body in order to increase hardness;
a key background color paint layer for color presentation, coated onto the key body;
an opaque paint layer coated onto the key background color paint layer;
a transparent marking portion formed by performing a laser processing according to a shape of a numeral, a character, or a symbol with respect to the key body so as to remove the key background color paint layer and the opaque paint layer;
a metallic vacuum deposition layer formed on the opaque paint layer and the transparent marking portion; and
a color-printed layer or a cellophane paper attached to the metallic vacuum deposition layer so as to present various colors.