JP4114753B2 - OSCILLATOR CIRCUIT, INFORMATION RECORDING / REPRODUCING DEVICE USING SAME, AND WIRELESS TRANSMITTER - Google Patents

Description

  The present invention relates to an oscillation circuit. In particular, the present invention relates to an oscillation circuit capable of changing an oscillation frequency, an information recording / reproducing apparatus using the oscillation circuit, and a wireless transmission apparatus.

A voltage-controlled oscillation circuit is used, for example, in an optical pickup or a PLL (Phase Locked Loop), and is generally set by changing an oscillation frequency according to an applied control voltage and oscillating and outputting a signal of the oscillation frequency. . An example of a voltage controlled oscillator in the prior art is connected so as to make a circuit of an inverting amplifier, a first charge / discharge circuit, and a second charge / discharge circuit. In this configuration, the phase of the inverted voltage signal from the inverting amplifier is delayed in stages by the first charging / discharging circuit and the second charging / discharging circuit, and the output of the second charging / discharging circuit is input to the inverting amplifier again. Is done. Since the phase of the inverted voltage signal that has made one round becomes the same as the initial phase again, the voltage-controlled oscillator can continuously oscillate by repeating the above processing. The oscillation frequency of the voltage controlled oscillator is mainly determined according to the magnitude of the charge / discharge current in the first charge / discharge circuit and the second charge / discharge circuit, and the magnitude of the charge / discharge current is further determined by the charge / discharge current. It is controlled by a control current having a larger current value level and easy control (see, for example, Patent Document 1).
JP-A-6-37599

  In the conventional technique, even if the charge / discharge current is very small, control is performed by the control current. Therefore, stable oscillation can be achieved even at a low oscillation frequency by stabilizing the current value level for control. On the other hand, in general, at the high oscillation frequency, further examination of the following problems is necessary. When an oscillation signal having a high oscillation frequency is oscillated and the oscillation signal is further amplified by a field effect transistor (FET) (hereinafter, this FET is referred to as an “amplification FET”), the current flowing through the amplification FET is If it is small, the operating speed of the amplifying FET becomes slow, and as a result, the oscillation signal is not sufficiently amplified. However, if the current passed through the amplifying FET is increased in order to sufficiently amplify the oscillation signal with a high oscillation frequency, more power than necessary is required when amplifying an oscillation signal with a low oscillation frequency instead of a high oscillation frequency. Is consumed.

  On the other hand, for a provider who provides an oscillation circuit incorporated in an LSI (Large-Scale Integrated circuit) or the like, it is desirable that the LSI can be used for general purposes in order to obtain a mass production effect. In addition, a user who incorporates an LSI into a device or the like needs a signal output with sufficient amplitude at an oscillation frequency set in the device, and desires an operation with low power consumption. Therefore, it is desired that the oscillation circuit has proper characteristics such as signal output and power consumption in a wide oscillation frequency range. In particular, when a user applies an oscillation circuit in a predetermined device and the oscillation frequency changes according to a predetermined setting during use of the device, the signal output and power consumption for each oscillation frequency Must meet certain requirements.

  The present inventor has recognized the above situation and made the present invention. The purpose of the present invention is to improve the characteristics of the oscillation signal and reduce the power consumption according to the oscillation frequency, and information using the oscillation circuit. It is to provide a recording / reproducing apparatus and a wireless transmission apparatus.

  One embodiment of the present invention is an oscillation circuit. This oscillation circuit can set the oscillation frequency of the oscillation signal. The oscillation signal generation circuit that outputs the oscillation signal with the oscillation frequency set, the amplifier that amplifies the output oscillation signal, and the voltage of the amplified oscillation signal It includes a conversion amplifier circuit that converts the current into a current and amplifies it, and a frequency-dependent adjustment circuit that adjusts the operating characteristics of the amplifier according to the settings of the oscillation signal generation circuit.

The amplification factor in the “amplifier” may be appropriately set according to the circuit. For example, when the amplification factor is larger than “1”, when the amplification factor is “1”, the amplification factor may be smaller than “1”. Shall be included.
“Setting content” indicates a setting related to the oscillation frequency, and the setting is made based on a current value, a voltage value, or other signals.

When the oscillation frequency of the oscillation signal is set high in the oscillation signal generation circuit, the frequency dependent adjustment circuit may increase the operating speed of the amplifier.
“High setting” is performed according to the magnitude of the voltage value or current value, or a predetermined signal, but it is only necessary that the oscillation frequency finally increase.

With the above oscillation circuit, the operating characteristics of the amplifier can be adjusted according to the oscillation frequency of the oscillation signal, so that if the oscillation frequency increases, the amplifier operates faster and can output an oscillation signal with a higher oscillation frequency. Become.
The oscillation signal generation circuit includes a ring oscillator and a drive circuit that causes a drive current to flow to the ring oscillator according to the set contents, and the frequency-dependent adjustment circuit causes a current corresponding to the drive current to flow to the amplifier, and the amplifier May be operated.

  Another embodiment of the present invention is also an oscillation circuit. This oscillation circuit includes an oscillation signal generation circuit that outputs a predetermined oscillation signal, an amplifier that amplifies the output oscillation signal, a conversion amplification circuit that converts and amplifies the voltage of the amplified oscillation signal into a current, and a conversion amplification circuit A setting circuit that sets the conversion characteristics of the amplifier, and an output-dependent adjustment circuit that adjusts the operating characteristics of the amplifier in accordance with the setting contents of the setting circuit.

In the setting circuit, when the current for converting the voltage of the oscillation signal into the current is set large, the output dependent adjustment circuit may increase the operation speed of the amplifier.
With the above oscillation circuit, the operational characteristics of the amplifier can be adjusted according to the setting for converting the voltage of the oscillation signal into current. For example, the current of the oscillation signal can be increased and output by high-speed operation of the amplifier. Is possible.

  According to the present invention, the characteristics of the oscillation signal can be improved and the power consumption can be reduced according to the oscillation frequency.

(Embodiment 1)
In the first embodiment, for the purpose of versatility, the manufacture is performed so that an oscillation signal having a wide range of oscillation frequencies can be oscillated, and the user sets a predetermined oscillation frequency and incorporates it into a predetermined device. The present invention relates to the presupposed high-frequency oscillation circuit. The high-frequency oscillation circuit in the present embodiment changes the oscillation frequency of the oscillation signal in accordance with the applied control voltage. For example, if the control voltage is high, the oscillation frequency is increased, and if the control voltage is low, the oscillation frequency is decreased. In addition, the amplitude of the oscillation signal voltage is sufficiently amplified by the amplification FET, and the amplified oscillation signal voltage is converted into a current. In particular, the high-frequency oscillation circuit according to the present embodiment increases the current flowing through the amplification FET when the control voltage is set high, and therefore can operate the amplification FET at high speed when the oscillation frequency is high. On the other hand, when the oscillation frequency is low, the current flowing through the amplifying FET can be reduced, so that power consumption can be reduced.

  FIG. 1 shows a high-frequency oscillation circuit 100 according to the first embodiment. The high frequency oscillation circuit 100 includes a voltage control type oscillation circuit 50, an amplifier 52, a conversion amplification circuit 54, and an adder 56. The voltage control type oscillation circuit 50 includes a voltage control type current source 58 and a signal oscillation circuit 60. The amplifier circuit 54 includes a first switch circuit 62, a second switch circuit 64, a first current value conversion amplifier circuit 66, a second current value conversion amplifier circuit 68, and a constant current source 70. As signals, a control voltage 306, an oscillator drive current 308, a first source oscillation signal 310, a second source oscillation signal 312, a first amplified oscillation signal 314, a second amplified oscillation signal 316, a conversion constant current 318, a first current. An oscillation signal 320, a second current oscillation signal 322, an amplifier drive current 324, an oscillator equivalent current 326, and a conversion equivalent current 328 are included.

  The voltage control type current source 58 applies a control voltage 306 and causes an oscillator driving current 308 and an oscillator equivalent current 326 to flow according to the magnitude of the control voltage 306. Here, the magnitudes of the oscillator driving current 308 and the oscillator equivalent current 326 have a proportional relationship, and both increase as the control voltage 306 increases.

  The signal oscillation circuit 60 outputs a first source oscillation signal 310 and a second source oscillation signal 312 having an oscillation frequency corresponding to the magnitude of the oscillator drive current 308. Specifically, when the oscillator driving current 308 is increased, the oscillation frequency is set higher. For example, the first source oscillation signal 310 and the second source oscillation signal 312 repeatedly have a maximum value and a minimum value appearing in a certain period like a sine wave, but enable differential amplification processing by the amplifier 52 described later. Therefore, a balance signal is configured. It should be noted that “balance signal” indicates a differential signal, while “unbalance signal” indicates a normal signal based on ground or the like.

  The amplifier 52 differentially amplifies the first source oscillation signal 310 and the second source oscillation signal 312, respectively, and outputs a first amplification oscillation signal 314 and a second amplification oscillation signal 316. The differential amplification process is executed for the purpose of increasing the drive capability in the first switch circuit 62 and the second switch circuit 64 described later. The first amplified oscillation signal 314 and the second amplified oscillation signal 316 have the same waveform as the first source oscillation signal 310 and the second source oscillation signal 312 and constitute a balance signal. The amplifying FET described above is included in the amplifier 52.

  The constant current source 70 supplies a conversion constant current 318 for converting the voltage of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 into a current. Here, the conversion constant current 318 is regulated to a constant value, and a conversion equivalent current 328 having a proportional relationship with the conversion constant current 318 is also output.

  The first switch circuit 62 converts the first amplified oscillation signal 314 into the first current oscillation signal 320. Here, if the value of the first amplified oscillation signal 314 is large, the value of the first current oscillation signal 320 is close to the value of the constant current for conversion 318, and if the value of the first amplified oscillation signal 314 is small, the first current oscillation signal 314 is close. The value of signal 320 is smaller. The second switch circuit 64 operates in the same manner as the first switch circuit 62, and converts the second amplified oscillation signal 316 into the second current oscillation signal 322.

  The first current value conversion amplification circuit 66 converts the value of the first current oscillation signal 320, and the second current value conversion amplification circuit 68 converts the value of the second current oscillation signal 322. Here, the converted first current oscillation signal 320 corresponds to the source current, and the value of the converted second current oscillation signal 322 corresponds to the sink current, and is based on switching in the first switch circuit 62 and the second switch circuit 64. Thus, the output current is switched between the sink current and the source current. Here, “output current” includes “sink current” and “source current”.

  The adder 56 causes the amplifier driving current 324, which is obtained by adding the oscillator equivalent current 326 and the conversion equivalent current 328, to flow through the amplifier 52. When the amplifier driving current 324 increases, the operation of the amplifier 52 becomes faster. That is, even if the first source oscillation signal 310 and the second source oscillation signal 312 fluctuate at a higher oscillation frequency, the amplifier drive current 324 increases, so that the operation of the amplifier 52 can follow the higher oscillation frequency, The amplitudes of the amplified oscillation signal 314 and the second amplified oscillation signal 316 become larger.

  Further, although details will be described later in Embodiment 2, since the conversion equivalent current 328 is also added to the amplifier drive current 324, the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 are further increased. Even in this case, the amplitudes of the first current oscillation signal 320 and the second current oscillation signal 322 are increased regardless of the value of the conversion constant current 318.

  FIG. 2 shows a time change of the first amplified oscillation signal 314 as an output signal of the amplifier 52. A solid line in the figure indicates a case where the amplifier driving current 324 is sufficiently large, and a dotted line in the figure indicates a case where the amplifier driving current 324 is small. If the amplifier driving current 324 is large, the operation of the amplifier 52 can sufficiently follow the fluctuation of the first source oscillation signal 310 having a high oscillation frequency, so that the amplitude of the first amplified oscillation signal 314 also increases. On the other hand, if the amplifier drive current 324 is small, the operation of the amplifier 52 cannot sufficiently follow the fluctuation of the first source oscillation signal 310, and therefore the amplitude of the first amplified oscillation signal 314 becomes smaller. The same applies to the second amplified oscillation signal 316.

  FIG. 3 shows the output current converted from the voltage by the conversion amplifier circuit 54. A solid line in the figure indicates a case where the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 are large, and a dotted line in the figure indicates that the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 are small. Show the case. The case where the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 are small assumes, for example, a case where the conversion equivalent current 328 is not added to the amplifier drive current 324. If the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 are large, the switching of the first switch circuit 62 and the second switch circuit 64 becomes fast, and the first current oscillation signal 320 and the second current oscillation are sufficiently obtained. Since the signal 322 can be converted, as a result, the amplitude of the output current converted by the conversion amplifier circuit 54 also increases. On the other hand, if the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 are small, they cannot be sufficiently converted into the first current oscillation signal 320 and the second current oscillation signal 322. As a result, the conversion amplification circuit 54 converts the amplitude. The output current amplitude is reduced.

  Here, the “amplitude of the output current” is defined by, for example, the sum of the maximum values of the sink current and the source current, the maximum value of the sink current, and the maximum value of the source current. These are not explicitly distinguished here.

  In the configuration of the high-frequency oscillation circuit 100 according to the present embodiment, the voltage-controlled oscillation circuit 50 and the amplifier 52 transmit a voltage balance signal based on differential processing, and the balance signal is finally converted into a current by the conversion amplifier circuit 54. It is converted to an unbalanced signal. Since the distortion component of the signal is also canceled between the balanced signals having such a configuration, the distortion component of the signal is reduced, and as a result, the harmonic component of electromagnetic interference (EMI) is reduced. Therefore, the high-frequency oscillation circuit 100 can output a signal that does not contain a harmonic component unnecessarily.

  The operation of the high-frequency oscillation circuit 100 configured as described above is as follows. When the control voltage 306 is increased, the oscillator driving current 308 and the oscillator equivalent current 326 that the voltage controlled current source 58 flows are also increased. The signal oscillation circuit 60 outputs the first source oscillation signal 310 and the second source oscillation signal 312 having higher oscillation frequencies when the oscillator driving current 308 increases. As the oscillator equivalent current 326 increases, the amplifier drive current 324 flowing from the adder 56 also increases. When the amplifier drive current 324 increases, the amplifier 52 converts the first source oscillation signal 310 and the second source oscillation signal 312 having a higher oscillation frequency into a first amplification oscillation signal 314 and a second amplification oscillation signal 316 having sufficiently large amplitudes, respectively. Amplify.

  The first switch circuit 62 and the second switch circuit 64 convert the first amplified oscillation signal 314 and the second amplified oscillation signal 316 to the first current oscillation signal 320 based on the conversion constant current 318 from the constant current source 70, respectively. The second current oscillation signal 322 is converted. The first current value conversion amplification circuit 66 and the second current value conversion amplification circuit 68 convert the values of the first current oscillation signal 320 and the second current oscillation signal 322, respectively, and further, the first switch circuit 62 and the second switch circuit The final output current is obtained by switching 64. Regardless of the magnitude of the control voltage 306, the conversion equivalent current 328 from the constant current source 70 is added to the amplifier drive current 324 and flows to the amplifier 52, so that the first switch circuit 62 and the second switch The amplitudes of the first current oscillation signal 320 and the second current oscillation signal 322 converted by the circuit 64 are closer to the value of the conversion constant current 318.

  According to the present embodiment, since the current corresponding to the oscillation frequency of the oscillation signal flows through the amplifier, the amplitude of the output current can be increased when the oscillation frequency is high, and the power consumption is low when the oscillation frequency is low. Power operation can be realized. In addition, since the current proportional to the current used to convert the voltage of the oscillation signal into current flows through the amplifier, the switching characteristics of the amplifier become faster, and the oscillation signal can be amplified to a larger amplitude voltage. Therefore, the amplitude of the output current can be increased.

(Embodiment 2)
The second embodiment is a high-frequency oscillation circuit similar to that of the first embodiment. However, in the first embodiment, the high-frequency oscillation circuit has been described using functional blocks, but in the second embodiment, the high-frequency oscillation circuit is a circuit such as an FET. This will be explained according to the arrangement.

FIG. 4 shows a high-frequency oscillation circuit 100 according to the second embodiment. In the figure, the same functional blocks and signals as those in FIG. 1 are denoted by the same reference numerals.
The variable current source 72 passes a current that changes according to the control voltage 306. The transistors Tr1 to Tr3 form a current mirror circuit, and an oscillator equivalent current 326 and an oscillator drive current 308 are supplied from the transistors Tr2 and Tr3, respectively. As described above, the oscillator driving current 308, the oscillator equivalent current 326, and the current from the variable current source 72 are in a proportional relationship with each other.

  Transistors Tr4 to Tr9 form a current mirror circuit, and transistors Tr10 to Tr14 also form a current mirror circuit. By these current mirror circuits, a current corresponding to the oscillator driving current 308 is supplied to the differential output type ring oscillator constituted by the first inverter 74, the second inverter 76, the third inverter 78, and the fourth inverter 80, respectively. . That is, as the oscillator drive current 308 increases, the current flowing through the ring oscillator increases, and the oscillation frequency of the first source oscillation signal 310 and the second source oscillation signal 312 output from the ring oscillator increases.

  The transistor Tr15 to the transistor Tr18, the transistor Tr23, and the transistor Tr24 constitute a differential amplifier, and the first source oscillation signal 310 and the second source oscillation signal 312 are respectively applied to the gate terminals of the transistor Tr23 and the transistor Tr24. Dynamic amplification processing is performed. The purpose of this differential amplification processing is to increase the drive capability of transistors Tr32 and Tr33, which will be described later, as in the first embodiment. In addition, since the transistors Tr19 to Tr22, the transistor Tr25, and the transistor Tr26 also constitute a differential amplifier, the first source oscillation signal 310 and the second source oscillation signal 312 are amplified in two stages, and the first amplified oscillation signal is obtained. 314 and the second amplified oscillation signal 316 are output. Further, the amplifier drive current 324 that flows through each differential amplifier will be described later.

  The transistor Tr41 and the transistor Tr40 constitute a current mirror circuit, and the constant current for conversion 318 from the variable current source 82 and the equivalent current for conversion 328 having a proportional relationship with the constant current for conversion 318 flow therethrough.

  The transistor Tr32 converts the first amplified oscillation signal 314 applied to the gate terminal into the first current oscillation signal 320. Here, since the transistor Tr32 is an n-channel type, when the value of the first amplified oscillation signal 314 increases, the value of the first current oscillation signal 320 also approaches the value of the conversion constant current 318. The transistor Tr33 performs the same operation as the transistor Tr32 and converts it into the second current oscillation signal 322. The transistor Tr34 and the transistor Tr35 form a current mirror circuit and convert the first output current having a proportional relationship with the first current oscillation signal 320. Further, the transistor Tr36 and the transistor Tr37, and the transistor Tr38 and the transistor Tr39 respectively constitute a current mirror circuit, and convert it into a second output current having a proportional relationship with the second current oscillation signal 322. Further, the first output current and the second output current become final output currents by switching between the transistor Tr32 and the transistor Tr33.

  The transistor Tr27, the transistor Tr28, and the transistor Tr30 form a current mirror circuit, and an amplifier drive current 324 that is proportional to the oscillator equivalent current 326 is supplied from the transistor Tr28 and the transistor Tr30. As described above, when the oscillator equivalent current 326 increases, the amplifier driving current 324 increases accordingly.

  The reason why the current proportional to the conversion equivalent current 328 is added to the amplifier drive current 324 is as follows. In order to increase the amplitude of the final output current, it is necessary to increase the conversion constant current 318. However, if the gate-source voltage of the transistor Tr32 and the transistor Tr33 is low, the switching operation of the transistor Tr32 and the transistor Tr33 is delayed, so that the amplitude of the first current oscillation signal 320 and the second current oscillation signal 322 is converted into a constant. The current 318 cannot be transmitted efficiently. Therefore, a conversion equivalent current 328 having a certain relationship with the conversion constant current 318 is supplied, and a current supplied from a current mirror circuit including the transistor Tr41, the transistor Tr31, and the transistor Tr29 is added to the amplifier drive current 324.

  As a result, the amplifier drive current 324 flowing through the differential amplifier is further increased, so that the operating characteristics of the differential amplifier become faster. Therefore, it is possible to follow fluctuations in the first source oscillation signal 310 and the second source oscillation signal 312, and the amplitude of the second amplified oscillation signal 316 of the first amplified oscillation signal 314 becomes sufficiently large. As a result, the maximum value of the gate-source voltage of the transistor Tr32 and the transistor Tr33 is increased, so that the switching operation of the transistor Tr32 and the transistor Tr33 is fast, and the conversion constant current 318 is efficiently converted into the final output current amplitude. Reportedly.

  2 shows the time change of the first amplified oscillation signal 314 or the second amplified oscillation signal 316 as the output signal of the amplifier 52, and FIG. 3 shows the output current converted from the voltage by the conversion amplification circuit 54. Since they are the same as those of the first embodiment, their description is omitted here.

  The operation of the high-frequency oscillation circuit 100 configured as described above is as follows. When the control voltage 306 is increased, the oscillator equivalent current 326 supplied by the transistor Tr2 and the oscillator drive current 308 supplied by the transistor Tr3 in the current mirror circuit are increased. If the oscillator drive current 308 increases, the oscillation frequency of the first source oscillation signal 310 and the second source oscillation signal 312 output from the first inverter 74, the second inverter 76, the third inverter 78, and the fourth inverter 80 increases. Become. In addition, when the oscillator equivalent current 326 increases, the amplifier driving current 324 flowing through the transistor Tr28 and the transistor Tr30 in the current mirror circuit also increases. If the amplifier drive current 324 increases, the amplifier 52 converts the first source oscillation signal 310 and the second source oscillation signal 312 having higher oscillation frequencies into the first amplified oscillation signal 314 and the second amplified oscillation signal 316 having sufficiently large amplitude. Amplify each.

  The transistors Tr32 and Tr33 are configured to convert the first amplified oscillation signal 314 and the second amplified oscillation signal 316 into the first current oscillation signal 320 and the second current oscillation signal based on the constant current 318 for conversion from the transistor Tr40 in the current mirror circuit. Convert to 322 respectively. The transistor Tr35 in the current mirror circuit converts the value of the first current oscillation signal 320, and the transistor Tr39 in another current mirror circuit converts the value of the second current oscillation signal 322. The converted current becomes a final output current in accordance with switching between the transistor Tr32 and the transistor Tr33. Note that, regardless of the magnitude of the control voltage 306, since the conversion equivalent current 328 is added to the amplifier drive current 324 by the transistors Tr31 and Tr29, the gate-source voltages of the transistors Tr32 and Tr33 are also increased. As a result, the amplitudes of the first current oscillation signal 320 and the second current oscillation signal 322 become closer to the value of the constant current 318 for conversion.

  According to the present embodiment, when the control voltage is increased, the oscillation frequency of the oscillation signal is increased and the transistor in the differential amplifier operates at high speed, so that the amplitude of the output current can be increased, while the oscillation frequency is low. In some cases, the transistor can be operated with low power consumption. In addition, since a current proportional to the current used for the transistor for converting the voltage of the oscillation signal into a current is passed through the transistor in the differential amplifier, the transistor in the differential amplifier operates at high speed, and the oscillation signal is amplified. Therefore, the voltage of the oscillation signal can be efficiently converted into a current.

(Embodiment 3)
In the third embodiment, a configuration of an apparatus or LSI to which the high-frequency oscillation circuit in the first or second embodiment is applied will be described.
FIG. 5A shows the configuration of the optical pickup 200 in the application example of the high-frequency oscillation circuit 100 according to the third embodiment. The optical pickup 200 includes a high-frequency oscillation circuit 100, a semiconductor laser chip 102, a monitoring photodiode 104, and a light receiving photodiode 108. The optical pickup 200 reads / writes a signal from / to a disk as a recording medium in an information recording / reproducing apparatus such as an optical disk apparatus or a magneto-optical disk apparatus.

  The semiconductor laser chip 102 emits a laser beam in accordance with a current supplied from a high-frequency oscillation circuit 100 described later. The high-frequency oscillation circuit 100 supplies a current to the semiconductor laser chip 102 based on a control signal indicated by a voltage from an APC (Automatic Power Control) circuit 106 described later.

  The optical system 110 irradiates a disk of a recording medium (not shown) as a light spot with a laser beam emitted from the semiconductor laser chip 102, and guides reflected light from the disk to a light receiving photodiode 108 described later.

  The light receiving photodiode 108 converts the reflected light into a current signal. Further, the current signal is converted into a voltage signal. The monitoring photodiode 104 converts a part of the laser beam emitted from the semiconductor laser chip 102 into a current signal. Here, part of the laser beam refers to a laser beam emitted from the side of the semiconductor laser chip 102 where the optical system 110 is not present.

  The APC circuit 106 outputs a control signal to the high-frequency oscillation circuit 100 based on the current signal output from the monitoring photodiode 104 so that the laser beam is always output from the semiconductor laser chip 102 at a constant power. Then, feedback control of the semiconductor laser chip 102 is performed. Here, the APC circuit 106 is provided for the following reason. Although it is necessary to keep the voltage signal level output from the optical pickup 200 at a predetermined level, the power of the laser beam output from the semiconductor laser chip 102 has individual differences and responds sensitively to temperature changes. Simply performing the same control on the chip 102 does not make the power of the laser beam constant, and therefore the output level of the voltage signal cannot be kept constant.

  On the other hand, since the high-frequency oscillation circuit 100 can increase the amplitude of the output current even at a high oscillation frequency as described in the first and second embodiments, the semiconductor laser chip 102 can stably emit a laser beam.

  FIG. 5B shows a configuration of the frequency conversion circuit 202 in the application example of the high-frequency oscillation circuit 100 according to the third embodiment. The frequency conversion circuit 202 includes a high-frequency oscillation circuit 100, a multiplication circuit 122, a BPF (Bandpass Filter) 124, and an amplifier 126. The frequency conversion circuit 202 converts a signal to be transmitted into a signal for transmission in the communication device. More specifically, in the wireless transmission device, a baseband signal to be transmitted or an intermediate frequency signal obtained by frequency-converting the baseband signal is frequency-converted into a radio frequency signal.

The signal generation unit 120 generates a signal to be transmitted as a baseband signal, and frequency-converts the baseband signal to an intermediate frequency.
The high-frequency oscillation circuit 100 inputs a voltage corresponding to a radio frequency used for transmission, and outputs a radio frequency signal.

  The multiplier circuit 122 converts the frequency of the intermediate frequency signal with the radio frequency signal. Further, the BPF 124 reduces the influence of harmonics generated by frequency conversion.

The amplifier 126 amplifies the output signal of the BPF 124 to a predetermined power in order to transmit it in the wireless propagation path.
Here, as described in the first and second embodiments, the high-frequency oscillation circuit 100 can output a large value of current even at a high oscillation frequency, so that the semiconductor laser chip 102 stably outputs a radio frequency signal. Is possible.

  FIG. 5C shows the configuration of the PLL 204 in the application example of the high-frequency oscillation circuit 100 according to the third embodiment. The PLL 204 includes a high-frequency oscillation circuit 100, a phase comparator 150, a loop filter 152, and a frequency divider 154.

  The phase comparator 150 compares the phase and frequency of a reference clock signal input from the outside and a reference clock signal input from the frequency divider 154, and outputs a DC signal proportional to the difference. The loop filter 152 removes the high frequency component of the input signal and outputs a control voltage. The high-frequency oscillation circuit 100 outputs a clock signal having a frequency corresponding to the input control voltage. Here, a clock signal having a frequency N times the frequency of the reference clock signal is output. The output clock signal is divided by 1 / N in the frequency divider 154 and input to the phase comparator 150 as a reference clock signal.

  According to the present embodiment, the high-frequency oscillation circuit that can increase the amplitude of the output current even at a high oscillation frequency and can realize an operation with low power consumption at a low oscillation frequency can be applied to various devices and LSIs.

  The correspondence between the present invention and the configuration according to the embodiment is illustrated. The “oscillation signal generation circuit” corresponds to the variable current source 72 of the voltage-controlled current source 58, the transistor Tr1, the transistor Tr3, and the signal oscillation circuit 60 in the current mirror circuit. “Amplifier” corresponds to the amplifier 52. The “conversion amplification circuit” corresponds to the conversion amplification circuit 54. The “frequency-dependent adjustment circuit” corresponds to the transistors Tr1 and Tr2 in the current mirror circuit of the voltage controlled current source 58 and the transistors Tr27, Tr28, and Tr30 in the current mirror circuit of the adder 56. The “ring oscillator” corresponds to the first inverter 74, the second inverter 76, the third inverter 78, and the fourth inverter 80 in the signal oscillation circuit 60. The “drive circuit” corresponds to the transistors Tr4 to Tr14 in the two current mirror circuits of the signal oscillation circuit 60.

  The “oscillation signal generation circuit” corresponds to the variable current source 72 of the voltage-controlled current source 58, the transistor Tr1, the transistor Tr3, and the signal oscillation circuit 60 in the current mirror circuit. “Amplifier” corresponds to the amplifier 52. The “conversion amplification circuit” corresponds to the conversion amplification circuit 54. The “setting circuit” corresponds to the constant current source 70. The “output-dependent adjustment circuit” corresponds to the transistor Tr41, the transistor Tr31, and the transistor Tr29 in the current mirror circuit of the constant current source 70 and the adder 56.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

  In the first to third embodiments, the signal oscillation circuit 60, the amplifier 52, and the conversion amplification circuit 54 are each configured by a combination of a plurality of transistors and signals on the premise of differential amplification processing, and transmit a balance signal. However, the present invention is not limited to this. For example, an unbalanced signal may be transmitted on the premise of an absolute amplification process. According to this modification, the number of components such as transistors constituting the high-frequency oscillation circuit 100 can be reduced. That is, it is only necessary to oscillate a current having the finally set oscillation frequency.

  In the second embodiment, the amplifier 52 is composed of two differential amplifiers. However, the present invention is not limited to this. For example, it may be configured by one differential amplifier or three or more differential amplifiers. According to this modification, the amplitudes of the first amplified oscillation signal 314 and the second amplified oscillation signal 316 can be changed. That is, the number of differential amplifiers corresponding to the values required for the first amplified oscillation signal 314 and the second amplified oscillation signal 316 output from the amplifier 52 may be provided.

1 is a diagram illustrating a high-frequency oscillation circuit according to a first embodiment. It is a figure which shows the output signal of the amplifier of FIG. It is a figure which shows the output current converted from the voltage in the conversion amplifier circuit of FIG. 6 is a diagram showing a high-frequency oscillation circuit according to Embodiment 2. FIG. FIGS. 5A to 5C are diagrams illustrating application examples of the high-frequency oscillation circuit according to the third embodiment.

Explanation of symbols

  50 voltage control type oscillation circuit, 52 amplifier, 54 conversion amplification circuit, 56 adder, 58 voltage control type current source, 60 signal oscillation circuit, 62 first switch circuit, 64 second switch circuit, 66 first current value conversion amplification Circuit, 68 second current value conversion amplifier circuit, 70 constant current source, 72 variable current source, 74 first inverter, 76 second inverter, 78 third inverter, 80 fourth inverter, 82 variable current source, 100 high frequency oscillation circuit 306, control voltage, 308 oscillator drive current, 310 first source oscillation signal, 312 second source oscillation signal, 314 first amplification oscillation signal, 316 second amplification oscillation signal, 318 constant current for conversion, 320 first current oscillation signal 322, second current oscillation signal, 324 amplifier drive current, 326 oscillator equivalent Flow, 328 conversion equivalent current, Tr1～Tr41 transistor.

Claims (3)

An oscillation signal generation circuit that outputs a predetermined oscillation signal according to an input voltage ;
A voltage-controlled current source that generates a current according to the input voltage;
An amplifier for amplifying the output oscillation signal;
A conversion amplifier circuit that converts the amplified oscillation signal voltage into current and amplifies the current;
A variable current source for setting the conversion characteristics of the conversion amplifier circuit ;
An adding circuit for adding the current generated from the voltage-controlled current source and the current of the variable current source to adjust the operating characteristics of the amplifier;
An oscillation circuit comprising: An information recording / reproducing apparatus comprising the oscillation circuit according to claim 1 . A radio transmission apparatus comprising the oscillation circuit according to claim 1 .

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