Background technology
Present data card product is mainly used in getting online without being tethered to a cable.Data card can be inserted on the USB interface or other data-interface of existing notebook computer, make notebook computer pass through the data card connecting Internet, surf the web, the application such as office and transfer of data.The operation principle of data card be with network interface card as a modulator-demodulator, utilize mobile communications network (such as GPRS, CDMA 1X) to come connecting Internet to realize online by existing mobile operator.
Data card usually is inserted on the USB interface of notebook computer and uses, have on the USB interface power supply+5V, data-, data+, four contacts, power supply ground, "+the 5V " of USB interface, " power supply ground " provide+the 5V power supply to data card, guarantee that data card equipment can work normally, " data+" and " data-" passage and the notebook computer of data card by USB interface carries out transfer of data.According to current at present USB standard, it is the external equipment power supply that USB interface can provide the voltage of 5V ± 5%, each interface maximum output current is 500mA, so its power output can not surpass 2.25W, and the external equipment that has surpassed this power is needs outfit external power supply just.USB interface on the notebook computer, follow the USB1.1 standard, it is the power supply of usb data card that USB interface can provide the voltage of 5V ± 5%, but each interface maximum output current is 500mA, therefore its power output can not surpass 2.25W, the external equipment that has surpassed this power is needs outfit external power supply just, can cause that not so notebook computer restarts, and power supply is burnt in serious meeting.
Power supply circuits in the data card mainly are by consisting of with the Switching Power Supply of current-limiting protection and the DC/DC voltage transitions chip of buck; after DC/DC voltage transitions chip, be aided with jumbo electric capacity; guarantee radio-frequency power amplifier (RFPA) normal operation of data card; when data card under GSM Burst pattern; for data card provides enough transient currents, to guarantee the transmitted power of wireless radio frequency modules when GSM opens of data card.But present data card does not have the functions such as current-limiting function and Anti-surging, is easy to move on the power supply with notebook host guard mode, causes that notebook host restarts, and seriously can burn out the power supply of notebook computer.And, data card is in the situation that the GSM work pattern, need very large transient current, need to be in the power supply circuits of data card jumbo electric capacity in parallel (generally being greater than 2000uF) satisfy the transmitted power of GSM, so not only volume is larger, and causes DC/DC conversion chip and the large bulk capacitance cost in parallel of the buck in the data card higher.
A kind of power supply plan that also has of existing data card is to adopt common DC/DC conversion chip and current limliting chip, be aided with jumbo electric capacity at DC/DC conversion chip output and consist of power supply circuits, guarantee the normal operation of radio-frequency power amplifier, under GSM Burst pattern, provide enough transient currents, the transmitted power when guaranteeing that GSM opens.But the shortcoming of this data card power supply circuits is when powered on moment and plug data card, because the error of sampling is larger, easily causes notebook computer power inadequate, causes to reset, and the cost of large bulk capacitance and current limliting chip is all higher simultaneously.And the dynamic response of normal DC/DC conversion chip is bad in the power supply circuits of available data card, the problem that causes data card to reset.
Summary of the invention
Based on the existing problem of above-mentioned prior art, embodiment of the present invention provides a kind of power supply circuits, power supply chip and data card of data card, the power supply circuits that can solve existing usb data card are stable for the power work that guarantees wireless radio frequency modules, need large bulk capacitance, raise the cost, and increase the problem of volume.
The embodiment of the invention provides a kind of power supply circuits of data card, comprising:
The slow startup and current-limiting circuit, its input connects power supply, is used for the electric current of power supply is carried out current limliting, realizes slow the startup;
The DC/DC voltage conversion circuit, be connected with the output of described slow startup and current-limiting circuit, its output connects wireless radio frequency modules, be used for the voltage of slow startup and current-limiting circuit output is carried out the transformation conversion, and the Voltage-output after will changing is to wireless radio frequency modules;
Electric capacity, be connected on the circuit between described slow startup and current-limiting circuit and the described DC/DC voltage conversion circuit, connection between the positive terminal of described electric capacity and slow startup and current-limiting circuit and the DC/DC voltage conversion circuit, the negative pole end ground connection of described electric capacity, described electric capacity is used for power supply is stored through the electric energy of slow startup and current-limiting circuit input, and institute's storage of electrical energy is offered described wireless radio frequency modules through described DC/DC voltage conversion circuit.
The embodiment of the invention also provides a kind of power supply chip of data card, comprising:
The slow startup and current-limiting circuit, its input connects power supply, is used for the electric current of power supply is carried out current limliting, realizes slow the startup;
The DC/DC voltage conversion circuit, be connected with the output of described slow startup and current-limiting circuit, its output connects wireless radio frequency modules, be used for the voltage of slow startup and current-limiting circuit output is carried out the transformation conversion, and the Voltage-output after will changing is to wireless radio frequency modules.
The embodiment of the invention further provides a kind of data card, comprising:
The power supply circuits of data card described above;
Wireless radio frequency modules links to each other with the output of the power supply circuits of described data card, is used for sending wireless signal and realizes radio communication.
Can be found out by the technical scheme that the invention described above execution mode provides, by the previous stage at the DC/DC voltage conversion circuit slow the startup and current-limiting circuit is set in the embodiment of the invention, improve the fast transient response ability of power supply circuits, and, appearance is arranged on DC/DC voltage conversion circuit front end in the power supply circuits, can be when slow startup and current-limiting circuit current limliting, for wireless radio frequency modules provides electric energy, so that the power supply of wireless radio frequency modules is more stable, simultaneously because the slow startup of increase and current-limiting circuit have also reduced the appearance value (electric capacity is compared the 2000uF capacity of traditional data card power supply circuits can reduce to 600uF) of electric capacity, can satisfy the power supply of stablizing wireless radio frequency modules, reduce the space that large bulk capacitance takies circuit board, also reduced the holistic cost of data card.
Embodiment
For ease of understanding, below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.
Embodiment one
The present embodiment provides a kind of power supply circuits of data card, be used in the data card, can reduce the capacity of energy storage usefulness electric capacity in the data card, when guaranteeing data card for electrical stability, can also reduce the cost of data card, as shown in Figure 1, these power supply circuits comprise: slow startup and current-limiting circuit, DC/DC voltage conversion circuit and electric capacity;
Wherein, the slow startup and current-limiting circuit, its input connects power supply, being used for the electric current of power supply is carried out the slow startup of current limliting realization, mainly is when electric current increases, and carries out current limliting, and cooperate with electric capacity with energy storage, be wireless radio frequency modules power supply by electric capacity, to realize slow the startup, guaranteed the stability of powering for wireless radio frequency modules;
The DC/DC voltage conversion circuit, be connected with the output of described slow startup and current-limiting circuit, its output connects wireless radio frequency modules, be used for the voltage of slow startup and current-limiting circuit output namely is input to the voltage of this DC/DC voltage conversion circuit) carry out the transformation conversion, and the Voltage-output after will changing is to wireless radio frequency modules;
Electric capacity, be connected on the circuit between described slow startup and current-limiting circuit and the described DC/DC voltage conversion circuit, connection between the positive terminal of described electric capacity and slow startup and current-limiting circuit and the DC/DC voltage conversion circuit, the negative pole end ground connection of described electric capacity, namely be equivalent to electric capacity in parallel with the DC/DC voltage conversion circuit, described electric capacity is used for power supply is stored through the electric energy of slow startup and current-limiting circuit input, and institute's storage of electrical energy is offered described wireless radio frequency modules through described DC/DC voltage conversion circuit.Electric capacity can the employing capacity be tantalum electric capacity or the polymer electric capacity of 600uF~800uF, has reduced capacity with respect to the electric capacity of traditional 2000uF, has saved cost.
Slow startup in the above-mentioned power supply circuits and current-limiting circuit comprise as shown in Figure 2: under-voltage sample circuit, temperature protection circuit, power switch circuit, current sampling circuit, magnetically coupled circuit, control logic circuit and control drive circuit;
Wherein, under-voltage sample circuit is connected with the input of power supply, is used for obtaining when power supply is under-voltage voltage sampling signal;
Temperature protection circuit is used for obtaining the temperature protection signal when described slow startup and current-limiting circuit surpass preset temperature, and this temperature protection signal is offered control logic circuit;
Power switch circuit is connected with the input of power supply, and its output is used for controlling in the mode of opening or cutting off the output of power supply as the output of described slow startup and current-limiting circuit;
Current sampling circuit is connected with the output of described power switch circuit through magnetically coupled circuit, obtains current sampling signal for the output current value of described power switch circuit is taken a sample;
Control logic circuit; be connected with described power switch circuit through the control drive circuit; any signal of the temperature protection signal that is used for the voltage sampling signal that gets access to according to the current sampling signal that gets access to from described current sampling circuit, from under-voltage sample circuit or gets access to from described temperature protection circuit generates control signal, and utilizes described control signal to drive the output that power supply was opened or cut off to described power switch circuit through described control drive circuit.
Can also arrange in above-mentioned slow startup and the current-limiting circuit and absorb the protective separation circuit; be connected in parallel with described power switch circuit; be used for absorbing the crest voltage of power supply, avoid crest voltage that described power switch circuit is damaged, protected described power switch circuit.
When on the data card that adopts above-mentioned power supply circuits is inserted in the USB interface of computer, surfing the Net, the power supply (being computer power supply) of input is after the slow startup and current-limiting circuit and DC/DC voltage conversion circuit of above-mentioned power supply circuits, offer the wireless radio frequency modules of data card, for wireless radio frequency modules provides operating voltage.Slow startup in these power supply circuits and the power switch circuit in the current-limiting circuit can be comprised of very little (milliohm rank) the MOS switching circuit of internal resistance, can carry out current limliting through power switch circuit to the input voltage that power supply provides and realize slow the startup; Under-voltage sample circuit can be monitored input voltage, in below voltage drops to 4.5V, and the USB port at data card place also needs to provide the electric current of 500mA, can affect computer power supply causes computer to reset, therefore, by the action of logic control circuit power ratio control switching circuit, cut off power supply and carry out under-voltage locking, avoid affecting power supply (being computer power supply) and cause computer to reset; Temperature protection circuit can send the temperature protection signal this slow startup and current-limiting circuit when surpassing preset temperature, and the action of logic control circuit power ratio control switching circuit is cut off power supply and carried out overtemperature prote; Current sampling circuit is taken a sample to electric current by programme control circut; the output current of data card is limited in the electric current of 400mA~700mA; can also monitor by current sampling circuit simultaneously the output current of this slow startup and current-limiting circuit through magnetically coupled circuit; to play the protection calculation electromechanical source, avoid affecting the problem that computer power supply causes computer to reset because being somebody's turn to do slow startup and current-limiting circuit overcurrent.
DC/DC voltage conversion circuit in the above-mentioned power supply circuits comprises as shown in Figure 3: circuit for power conversion (circuit for power conversion can be made of 2 metal-oxide-semiconductors), feedback circuit, current sampling circuit, voltage sample circuit, thermal protection circuit and logic control circuit;
Wherein, circuit for power conversion comprises input, output and two control ends; Described input is connected with the output of described slow startup and current-limiting circuit, described output is connected with described wireless radio frequency modules, two control ends connect through drive circuit andlogic control circuit respectively, be used for conducting or the disconnection of control inputs, output voltage, adjust conducting or can realize that the transformation from the input voltage to the output voltage changes opening time;
Feedback circuit, its input is connected with the output of described circuit for power conversion, its output is connected with voltage sample circuit with current sampling circuit respectively, be used for current feedback with the output of described circuit for power conversion to current sampling circuit, with the Voltage Feedback of the output of described circuit for power conversion to voltage sample circuit;
Current sampling circuit is connected with described feedback circuit; Be used for the electric current of the output of the described circuit for power conversion of described feedback circuit feedback taken a sample and obtain current sampling signal;
Voltage sample circuit is connected with described feedback circuit; Be used for from described logic control circuit, the output voltage of the described circuit for power conversion of described feedback circuit feedback is taken a sample obtains voltage sampling signal;
Thermal protection circuit is used for obtaining hot guard signal when this DC/DC voltage conversion circuit surpasses preset temperature;
Logic control circuit, comprise the two-way output, one road output is connected with a control end of described circuit for power conversion through one drive circuit, another road output is connected with another control end of circuit for power conversion through another drive circuit, be used for controlling opening or opening time of described circuit for power conversion according to the current sampling signal that gets access to from described current sampling circuit or from the voltage signal of described voltage sample circuit; And according to the hot guard signal that gets access to from described thermal protection circuit, disconnect described circuit for power conversion.
Circuit for power conversion in the above-mentioned DC/DC voltage conversion circuit, mainly formed by two metal-oxide-semiconductors and (also can adopt power consumption, other type of switch element that meets the demands such as heatproof, such as triode etc.), a upper metal-oxide-semiconductor is arranged on the input channel, a lower metal-oxide-semiconductor arranges on the output channel, during upper MOS conducting on input channel, then the lower MOS on output channel disconnects, if when being provided with the lower metal-oxide-semiconductor conducting on the output channel, then going up metal-oxide-semiconductor disconnects, therefore can the power ratio control change-over circuit in constantly conducting of difference or shutoff, thereby realize realizing input voltage is transformed to suitable output voltage by the control model of pulse-width modulation, thereby make output voltage after this DC/DC voltage conversion circuit conversion can satisfy the requirement of the operating voltage of the wireless radio frequency modules that the DC/DC voltage conversion circuit connects.For keeping output voltage stabilization, can realize by the power tube ON time that is adjusted in unit interval internal power change-over circuit according to input-output voltage ratio and loading condition.
Above-mentioned this DC/DC voltage conversion circuit has preferably dynamic response, can satisfy the larger requirement of data card dynamic power consumption, when the load current of data card is undergone mutation, be unlikely to cause the sudden change of the output voltage of the slow startup of front end and current-limiting circuit, can avoid causing computer to reset because power supply is influenced, and data card cause the problem that resets and can't work.
Power supply circuits in the present embodiment, by the previous stage at the DC/DC voltage conversion circuit slow the startup and current-limiting circuit is set, current limliting and soft start function by slow startup and current-limiting circuit, improve the fast transient response ability of power supply circuits, and, energy storage electricity consumption appearance is arranged on DC/DC voltage conversion circuit front end, so that the store electrical energy of electric capacity can offer wireless radio frequency modules when slow startup and current-limiting circuit current limliting, make the power supply of wireless radio frequency modules more stable, also reduced simultaneously the capacitance (this electric capacity compare the 2000uF capacity of traditional data card power supply circuits reduce to 600uF) of energy storage with electric capacity, not only reduce the space that tradition use large bulk capacitance takies circuit board, also reduced the holistic cost of data card.
Embodiment two
The present embodiment provides a kind of power supply chip of data card, be based on the chip of the power supply circuits that embodiment one provides, as shown in Figure 3, this chip comprises: slow startup and current-limiting circuit and DC/DC voltage conversion circuit, slow startup and current-limiting circuit and DC/DC voltage conversion circuit all adopt slow startup and current-limiting circuit and the DC/DC voltage conversion circuit that provides in above-described embodiment one, slow start and the output of current-limiting circuit be encapsulated in the chip body 1 after DC/DC voltage conversion circuit input is connected.Chip body 1 be provided with slow start and current-limiting circuit input terminal 2, slow start and the output of current-limiting circuit and DC/DC voltage conversion circuit input between be connected the energy storage leading-out terminal 3 of electric capacity and the lead-out terminal 4 of DC/DC voltage conversion circuit.
This chip can be arranged in the data card, cooperate with electric capacity with energy storage, power supply circuits as data card, only use than the energy storage of low capacity with electric capacity (generally using 600uF), can satisfy transmitted power and the stability requirement of log-on data card GSM pattern, can reduce the space that large bulk capacitance takies circuit board, also reduce the holistic cost of data card.
Embodiment three
The present embodiment provides a kind of data card, and as shown in Figure 5, this terminal comprises:
Power supply circuits 21 and wireless radio frequency modules 22; Wherein, power supply circuits 21 adopt the power supply circuits of the data card that provides in above-described embodiment one, also can adopt the power supply chip that provides among the embodiment two;
The output of described power supply circuits 21 is with after wireless radio frequency modules 22 is electrically connected, be encapsulated in the data card body (not shown), the data card body is provided with connecting interface, connecting interface comprises power interface and data-interface, power interface is electrically connected with the input of described power supply circuits, is used for sending wireless signal and makes this data card realize radio communication.This data card is owing to having the power supply circuits of current limliting, soft start function, can not move guard mode on the power supply with the notebook computer at place, avoided starting the problem that the notebook computer that causes resets and restarts by data card.
In sum, by the previous stage at the DC/DC voltage conversion circuit slow the startup and current-limiting circuit is set in the embodiment of the invention, current limliting and soft start function by slow startup and current-limiting circuit, improve the fast transient response ability of power supply circuits, and, appearance is arranged on DC/DC voltage conversion circuit front end in the power supply circuits, can be when slow startup and current-limiting circuit current limliting, for wireless radio frequency modules provides electric energy, so that the power supply of wireless radio frequency modules is more stable, simultaneously because the slow startup of increase and current-limiting circuit have also reduced the appearance value (electric capacity is compared the 2000uF capacity of traditional data card power supply circuits can reduce to 600uF) of electric capacity, can satisfy the power supply of stablizing wireless radio frequency modules, reduce the space that large bulk capacitance takies circuit board, also reduced the holistic cost of data card.
The above; only for the better embodiment of the present invention, but protection scope of the present invention is not limited to this, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.