CN204156831U - Ramp generator and imageing sensor - Google Patents
Ramp generator and imageing sensor Download PDFInfo
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- CN204156831U CN204156831U CN201420697134.9U CN201420697134U CN204156831U CN 204156831 U CN204156831 U CN 204156831U CN 201420697134 U CN201420697134 U CN 201420697134U CN 204156831 U CN204156831 U CN 204156831U
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Abstract
A kind of ramp generator and imageing sensor, ramp generator comprises: operational amplifier, first electric capacity and at least one first switching capacity unit, the first switching capacity unit comprises: the first switch, second switch, the 3rd switch, the 4th switch and the second electric capacity; The negative-phase input of the first end concatenation operation amplifier of the first switch and output, the normal phase input end of first end concatenation operation amplifier of second switch and the first end of the first electric capacity, second end of the 3rd switch is suitable for input first voltage, second end of the 4th switch is suitable for input second voltage, and the magnitude of voltage of the second voltage and the first voltage is unequal; In same first switching capacity unit, the second end of the first switch connects the second end of second switch and the first end of the second electric capacity, and the first end of the 3rd switch connects the first end of the 4th switch and the second end of the second electric capacity; Second end ground connection of the first electric capacity; The capacitance of the first electric capacity is greater than the capacitance of the second electric capacity.
Description
Technical field
The utility model relates to electronic applications, particularly relates to a kind of ramp generator and imageing sensor.
Background technology
In the image sensor, along with the continuous expansion of pixel unit array scale, traditional chip-scale analog to digital converter can not meet the requirement of high frame per second, so high frame rate image transducer adopts the analog to digital converter of row level, wherein single slope analog-to-digital converter (single slope analog to digital converter, SSADC) have and only need little area and power consumption just can realize high-precision feature, be widely used in the imageing sensor of high pixel high frame per second.In SS ADC, need slope (ramp) signal as the comparative level of comparator, its precision directly has influence on the output accuracy of SS ADC, so how producing a high-precision ramp signal is a very important research topic.
The generation of traditional ramp signal, a kind of method is by current steer (current steering) structure, produces ramp signal by constantly increasing the electric current flowing through fixed resistance.Another kind method is integration (integrating) structure, adopts fixing electric current constantly to fixed capacity charging, produces a continuous print ramp signal.These two kinds of ramp signal generator at a high speed and heavy load applies time, all there is long problem signal settling time, thus cause precision to be difficult to reach application requirement.
Utility model content
The problem that the utility model solves be existing ramp signal generator at a high speed and heavy load applies time, there is long problem signal settling time.
For solving the problem, the utility model provides a kind of ramp generator, comprise: operational amplifier, first electric capacity and the first switching capacity group, described first switching capacity group comprises at least one first switching capacity unit, and described first switching capacity unit comprises: the first switch, second switch, the 3rd switch, the 4th switch and the second electric capacity;
The first end of described first switch connects negative-phase input and the output of described operational amplifier, the first end of described second switch connects the normal phase input end of described operational amplifier and the first end of the first electric capacity, second end of described 3rd switch is suitable for input first voltage, second end of described 4th switch is suitable for input second voltage, and the magnitude of voltage of described second voltage and the first voltage is unequal;
In same first switching capacity unit, the second end of described first switch connects the second end of described second switch and the first end of the second electric capacity, and the first end of described 3rd switch connects the described first end of the 4th switch and the second end of the second electric capacity;
Second end ground connection of described first electric capacity;
The capacitance of described first electric capacity is greater than the capacitance of described second electric capacity.
Optionally, described ramp generator also comprises: be suitable for output first control signal, the second control signal, the 3rd control signal and the 4th controls signal to needs the first switching capacity unit of work to start the described switch control unit needing the first switching capacity unit of work;
Described first control signal is suitable for the closed and disconnected controlling described first switch, described second control signal is suitable for the closed and disconnected controlling described second switch, described 3rd control signal is suitable for the closed and disconnected controlling described 3rd switch, and described 4th control signal is suitable for the closed and disconnected controlling described 4th switch;
Described second control signal is the inversion signal of described first control signal, and described 4th control signal is the inversion signal of described 3rd control signal, and described first control signal and the 3rd control signal are with frequency in-phase signal.
Optionally, the described quantity needing the first switching capacity unit of work is multiple, and described switch control unit is suitable for predetermined order and starts described the first switching capacity unit needing work successively.
Optionally, described predesigned order is relevant to the ramp signal slope that described ramp generator exports.
Optionally, described switch control unit is suitable for first exporting described second control signal and the 4th and controls signal to the first switching capacity unit all needing work, then exports described first control signal and the 3rd successively by described predesigned order and control signal to described the first switching capacity unit needing work.
Optionally, described first control signal and the second control signal are pulse signal, and the amplitude of described pulse signal is followed the first end magnitude of voltage increase of described first electric capacity and increases.
Optionally, described ramp generator also comprises second switch capacitance group, described second switch capacitance group comprises at least one second switch capacitor cell, described second switch capacitor cell comprises: the 5th switch, the 6th switch, the 7th switch, the 8th switch and the 3rd electric capacity, and the capacitance of described 3rd electric capacity is equal with the capacitance of described second electric capacity;
The first end of described 5th switch connects first input end and the output of described operational amplifier, the first end of described 6th switch connects the second input of described operational amplifier and the first end of the first electric capacity, second end of described 7th switch is suitable for inputting described first voltage, and the second end of described 8th switch is suitable for inputting described second voltage;
In same second switch capacitor cell, the second end of described 5th switch connects the second end of described 6th switch and the first end of the 3rd electric capacity, and the first end of described 7th switch connects the first end of described 8th switch and the second end of the 3rd electric capacity.
Optionally, described switch control unit is also suitable for output the 5th control signal, the 6th control signal, the 7th control signal and the 8th controls signal to needs the second switch capacitor cell of work to start the described second switch capacitor cell needing work;
Described 5th control signal is suitable for the closed and disconnected controlling described 5th switch, described 6th control signal is suitable for the closed and disconnected controlling described 6th switch, described 7th control signal is suitable for the closed and disconnected controlling described 7th switch, and described 8th control signal is suitable for the closed and disconnected controlling described 8th switch;
Described 5th control signal is the inversion signal of described first control signal, described 6th control signal is the inversion signal of described second control signal, described 7th control signal is the inversion signal of described 3rd control signal, and described 8th control signal is the inversion signal of described 4th control signal.
The utility model embodiment also provides a kind of imageing sensor, comprising: ramp generator and analog to digital converter, and described ramp generator connects described analog to digital converter.
Optionally, the required precision of described analog to digital converter is relevant to the capacitance ratio of described first electric capacity and the second electric capacity.
Compared with prior art, the ramp generator that the technical solution of the utility model provides can adopt less equivalent capacity to carry out discharge and recharge, reduces ramp signal settling time, can meet high-precision requirement.
Accompanying drawing explanation
Fig. 1 is a structural representation of the ramp generator of the utility model embodiment;
Fig. 2 is the first switching capacity group structural representation of the utility model embodiment;
Fig. 3 is an equivalent structure schematic diagram of the ramp generator of the utility model embodiment;
Fig. 4 is another equivalent structure schematic diagram of the ramp generator of the utility model embodiment;
Fig. 5 is the waveform schematic diagram of the ramp signal of the utility model embodiment;
Fig. 6 is another structural representation of the ramp generator of the utility model embodiment.
Embodiment
For enabling above-mentioned purpose of the present utility model, feature and advantage more become apparent, and are described in detail specific embodiment of the utility model below in conjunction with accompanying drawing.
As shown in Figure 1, the utility model embodiment provides a kind of ramp generator, comprising: operational amplifier Opamp, the first electric capacity C1 and the first switching capacity group 1.
Shown in composition graphs 2, described first switching capacity group 1 comprises at least one first switching capacity unit.Described first switching capacity unit comprises: the first switch, second switch, the 3rd switch, the 4th switch and the second electric capacity C2.The first end of described first switch connects negative-phase input and the output bufout of described operational amplifier Opamp, the first end of described second switch connects the normal phase input end of described operational amplifier Opamp and the first end Vramp of the first electric capacity C1, second end of described 3rd switch is suitable for input first voltage, second end of described 4th switch is suitable for input second voltage Voft, the magnitude of voltage of described second voltage Voft and the magnitude of voltage of the first voltage unequal; In same first switching capacity unit, the second end of described first switch connects the second end of described second switch and the first end of the second electric capacity C2, and the first end of described 3rd switch connects the first end of described 4th switch and second end of the second electric capacity C2; The second end ground connection GND of described first electric capacity C1.The capacitance of described first electric capacity is greater than the capacitance of described second electric capacity.When the magnitude of voltage of the second voltage Voft is greater than the value of the first voltage, the ramp signal slope that ramp generator exports is greater than 0; When the magnitude of voltage of the second voltage Voft is less than the value of the first voltage, the ramp signal slope that ramp generator exports is less than 0.For the ease of understand, following examples all for the first voltage for ground voltage and the value that the magnitude of voltage of the second voltage Voft is greater than the first voltage be described.
For 4 the first switching capacity unit in Fig. 2.First switching capacity group 1 comprises: the 1st the first switching capacity unit 11, the 2nd the first switching capacity unit 12, the 3rd the first switching capacity unit 13 and the 4th the first switching capacity unit 14.
1st the first switching capacity unit 11 comprises: the first switch Φ 11, second switch Φ 21, the 3rd switch Φ 31, the 4th switch Φ 41 and the second electric capacity C2.2nd the first switching capacity unit 12 comprises: the first switch Φ 12, second switch Φ 22, the 3rd switch Φ 32, the 4th switch Φ 42 and the second electric capacity C2.3rd the first switching capacity unit 13 comprises: the first switch Φ 13, second switch Φ 23, the 3rd switch Φ 33, the 4th switch Φ 43 and the second electric capacity C2.4th the first switching capacity unit 14 comprises: the first switch Φ 14, second switch Φ 24, the 3rd switch Φ 34, the 4th switch Φ 44 and the second electric capacity C2.
The first switch in whole first switching capacity unit, the i.e. negative-phase input of first end equal concatenation operation amplifier Opamp of the first switch Φ 11, first switch Φ 12, first switch Φ 13 and the first switch Φ 14 and the output bufout of operational amplifier Opamp.Second switch in whole first switching capacity unit, the i.e. normal phase input end of first end equal concatenation operation amplifier Opamp of second switch Φ 21, second switch Φ 22, second switch Φ 23 and second switch Φ 24 and the first end Vramp of the first electric capacity C1.The 3rd switch in whole first switching capacity unit, namely second end of the 3rd switch Φ 31, the 3rd switch Φ 32, the 3rd switch Φ 33 and the 3rd switch Φ 34 is all suitable for ground connection GND.The 4th switch in whole first switching capacity unit, namely second end of the 4th switch Φ 41, the 4th switch Φ 42, the 4th switch Φ 43 and the 4th switch Φ 44 is all suitable for input second voltage Voft.
In each first switching capacity unit, the annexation of the first switch, second switch, the 3rd switch, the 4th switch and the second electric capacity is identical, connect second end of second switch Φ 21 and the first end of the second electric capacity C2 for second end of the 1st the first switching capacity unit 11: the first switch Φ 11, the first end of the 3rd switch Φ 31 connects the first end of the 4th switch Φ 41 and second end of the second electric capacity C2.
Ramp generator described in the present embodiment can also comprise: switch control unit.
Described switch control unit is suitable for output first control signal, the second control signal, the 3rd control signal and the 4th controls signal to needs the first switching capacity unit of work to start described the first switching capacity unit needing work.Described first control signal is suitable for the closed and disconnected controlling described first switch, described second control signal is suitable for the closed and disconnected controlling described second switch, described 3rd control signal is suitable for the closed and disconnected controlling described 3rd switch, and described 4th control signal is suitable for the closed and disconnected controlling described 4th switch.
Wherein, described second control signal is the inversion signal of described first control signal, and described 4th control signal is the inversion signal of described 3rd control signal, and described first control signal and the 3rd control signal are with frequency in-phase signal.Therefore, after the first switching capacity unit is activated, the first switch and the 3rd switch be closed or disconnection simultaneously, and second switch and the 4th switch be closed or disconnection simultaneously; First switch and the 3rd switch are then contrary with the 4th on off state with second switch, and when namely the first switch and the 3rd switch close, second switch and the 4th switch disconnect, and when the first switch and the 3rd switch disconnect, second switch and the 4th switch close.
First control signal, the second control signal, the 3rd control signal and the 4th control signal can be all pulse signal, the pulse signal of one-period has phase place 1 and phase place 2 two states, and the pulse signal in cycle constantly switches between phase place 1 and phase place 2 two states.Such as, during phase place 1, pulse signal is high level, and during phase place 2, pulse signal is low level.
A first switching capacity unit 11 is only comprised for ramp generator, when the first control signal and the 3rd control signal be phase place 1 state, the second control signal and the 4th control signal be phase place 2 state time, first switch and the 3rd switch close and second switch and the 4th switch disconnect, and the equivalent electric circuit of described ramp generator as shown in Figure 3.In this case, only to the second electric capacity C2 discharge and recharge.
When the first control signal and the 3rd control signal are state when phase place 2 state, the second control signal and the 4th control signal are phase place 1, first switch and the 3rd switch disconnect and second switch and the 4th switch close, and the equivalent electric circuit of described ramp generator as shown in Figure 4.In this case, the first electric capacity C1 and the second electric capacity C2 is connected in series, and equivalent capacity is less than the second electric capacity C2.
As can be seen from above-mentioned analysis, no matter the present embodiment is in phase place 1 state or phase place 2 state, and the equivalent capacity for discharge and recharge is all less, and corresponding RC postpones just very little, can realize the quick foundation of signal.
Equivalent electric circuit according to Fig. 3, the total electrical charge Q1 be stored on the first electric capacity C1 and the second electric capacity C2 is:
Q1=Vramp (n) * (C2+C1) (formula 1)
Vramp (n) in formula 1 represents the magnitude of voltage of the first end Vramp of the first electric capacity C1, and C2 represents the capacitance of the second electric capacity C2, and C1 represents the capacitance of the first electric capacity C1.
Equivalent electric circuit according to Fig. 4, the total electrical charge Q2 be stored on the first electric capacity C1 and the second electric capacity C2 is:
Q2=(Vramp (n+1)-Voft) * C2+Vramp (n+1) * C1 (formula 2)
Vramp (n+1) in formula 2 represents the magnitude of voltage of the first end Vramp of the first electric capacity C1, and Voft represents the magnitude of voltage of the second voltage Voft.
According to charge conservation theorem:
Q1=Q2 (formula 3)
Suppose: △ Vramp=Vramp (n+1)-Vramp (n) (formula 4)
Can be drawn by formula 1 to formula 4:
△ Vramp represents the height of each step in ramp signal, as can be seen from formula 5, by the selected capacitance of the first electric capacity C1 and the second electric capacity C2 and the magnitude of voltage of the second voltage Voft, the ramp signal that shoulder height changes such as just can to obtain.This that is, ramp signal has the very good linearity, integral nonlinearity (Integral nonlinearity, INL) and differential nonlinearity (Differential nonlinearity, DNL) all smaller.
First electric capacity C1 can regard the electric capacity that one comprises the load of ramp generator as, can find out that the first electric capacity C1 can not affect the settling time of signal substantially from upper surface analysis, so the ramp generator of the present embodiment can drive very large load.
The ramp generator of the present embodiment can be applied in the image sensor, is connected with analog to digital converter, and described analog to digital converter can be single slope analog-to-digital converter.When ramp generator connection mode number converter, described first electric capacity C1 can be relevant to precision needed for described analog to digital converter with the capacitance ratio of the second electric capacity C2.Suppose, analog to digital converter needs the precision reaching 11, and accessible range of signal is 1V, and so in ramp signal, the height △ Vramp of each step just approximates 0.5mV.When the magnitude of voltage of the second voltage Voft is 0.4V, the capacitance ratio that can obtain the first electric capacity C1 and the second electric capacity C2 according to formula 5 is 799:1.
All there is photon shot noise (photon shot noise) in imageing sensor, it can increase along with the increase of input signal.And the quantizing noise of analog to digital converter, do not change with input signal.So when input signal is larger, photon shot noise will be occupied an leading position, now the performance of analog to digital converter will be higher than required value, can reduce precision.Performance on ramp signal be exactly: when input signal is larger the slope of ramp signal can be greater than input signal less time ramp signal slope.Like this for identical signal transacting scope, the change-over time of analog to digital converter can be reduced, better be suitable for the high pixel application of high speed of imageing sensor.For this reason, ramp generator can produce the ramp signal shown in Fig. 5.Ramp signal shown in Fig. 5 is divided into three intervals, the ramp signal slope in each interval is different.
When the capacitance of the first electric capacity C1 is much larger than the capacitance of the second electric capacity C2, formula 5 can be reduced to:
As can be seen from formula 6, realized the change of ramp signal slope by the quantity changing the second electric capacity C2 work in the first switching capacity group.Therefore, need the quantity of the first switching capacity unit of work can be multiple described in the utility model embodiment, switch control unit be suitable for predetermined order and starts described the first switching capacity unit needing work successively.Described predesigned order can be determined according to the ramp signal slope of required output.
Still for the ramp signal shown in Fig. 5, when first is interval, ramp generator starts a first switching capacity unit, namely accesses a second electric capacity C2; When second is interval, ramp generator starts two the first switching capacity unit, namely accesses two the second electric capacity C2; When the 3rd is interval, ramp generator starts four the first switching capacity unit, namely accesses four the second electric capacity C2.
Concrete, composition graphs 2 and Fig. 5, during t0 to the t1 moment, switch control unit exports the first control signal respectively, the second control signal, the 3rd control signal and the 4th control signal to the first switch Φ 11, second switch Φ 21 in the 1st the first switching capacity unit 11, the 3rd switch Φ 31, the 4th switch Φ 41, to start the 1st the first switching capacity unit 11, thus an access second electric capacity C2.During t1 to the t2 moment, the first control signal produced, the second control signal, the 3rd control signal and the 4th control signal are exported again to the first switch Φ 12, second switch Φ 22 in the 2nd the first switching capacity unit 12, the 3rd switch Φ 32, the 4th switch Φ 42 by switch control unit, to start the 2nd the first switching capacity unit 12, thus add a second electric capacity C2.During t2 to the t3 moment, the first control signal that switch control unit will produce again, second control signal, 3rd control signal and the 4th control signal export the first switch Φ 13 in the 3rd the first switching capacity unit 13 to, second switch Φ 23, 3rd switch Φ 33, the first switch Φ 14 in 4th switch Φ 43 and the 4th the first switching capacity unit 14, second switch Φ 24, 3rd switch Φ 34, 4th switch Φ 44, to start the 3rd the first switching capacity unit 13 and the 4th the first switching capacity unit 14, thus turn increase two the second electric capacity C2.
In above process, described switch control unit first can also export described second control signal and the 4th and control signal to the first switching capacity unit all needing work, then exports described first control signal and the 3rd successively by described predesigned order and control signal to described the first switching capacity unit needing work.
Concrete, during t0 to the t1 moment, the first control signal that switch control unit will produce, second control signal, 3rd control signal and the 4th control signal export the first switch Φ 11 in the 1st the first switching capacity unit 11 to, second switch Φ 21, 3rd switch Φ 31, 4th switch Φ 41, to start the 1st the first switching capacity unit 11, and export the second control signal produced and the 4th control signal in the 2nd the first switching capacity unit 12 second switch Φ 22 and the 4th switch Φ 42, second switch Φ 24 in second switch Φ 23 in 3rd the first switching capacity unit 13 and the 4th switch Φ 43 and the 4th the first switching capacity unit 14 and the 4th switch Φ 44.During t1 to the t2 moment, switch control unit exports the first control signal produced and the 3rd control signal to the first switch Φ 12 in the 2nd the first switching capacity unit 12 and the 3rd switch Φ 32, to start the 2nd the first switching capacity unit 12 again.During t2 to the t3 moment, switch control unit exports the first control signal produced and the 3rd control signal to the first switch Φ 13 in the 3rd the first switching capacity unit 13 and the first switch Φ 14 in the 3rd switch Φ 33 and the 4th the first switching capacity unit 14 and the 3rd switch Φ 34, to start the 3rd the first switching capacity unit 13 and the 4th the first switching capacity unit 14 again.This mode can start the first switching capacity unit within the shorter time.
The first switch described in the present embodiment, second switch, the 3rd switch and the 4th switch can be metal-oxide-semiconductor.
The grid of the first switch and second switch receives the first control signal and the second control signal, source electrode connects the first end Vramp of the first electric capacity C1 and the output bufout of operational amplifier Opamp, and these two terminal voltages are all along with the first end Vramp capacitance change of the first electric capacity C1 becomes large greatly.Along with the magnitude of voltage of the first end Vramp of the first electric capacity C1 is increasing, the voltage being applied to the first switch and second switch source electrode is also increasing, and this causes the conducting resistance of metal-oxide-semiconductor also thereupon larger.
In order to solve the problem, the pulse amplitude of the first control signal that the present embodiment switch control unit produces and the second control signal is followed the first end Vramp magnitude of voltage increase of described first electric capacity C1 and increases.That is, the first end Vramp magnitude of voltage of the first electric capacity C1 increases how many, and the pulse amplitude of the first control signal just increases how many, the voltage difference Vgs between grid and source electrode is remained unchanged, thus conducting resistance remains unchanged, reduces the non-linear of switch.
Because the 3rd switch and the 4th switch are all connected on fixed potential, conducting resistance is constant, so the 3rd control signal described in the present embodiment and the 4th control signal can adopt the current potential forced down than power electric, thus reduce Charge injection effect and the clock feed-through effect of the 3rd switch and the 4th switch.
For the consideration identical with the 4th switch with the 3rd switch, voltage difference Vgs between the grid of the first switch and second switch and source electrode also can be less than supply voltage, and the first switch and second switch are made in DEEP NWELL, substrate and source electrode are connected together, reduce body bias effect, thus the voltage difference Vgs that can reduce further between grid and source electrode and switch is non-linear.
As shown in Figure 6, the ramp generator described in the present embodiment can also comprise: second switch capacitance group 2.
Described second switch capacitance group 2 comprises at least one second switch capacitor cell, described second switch capacitor cell comprises: the 5th switch, the 6th switch, the 7th switch, the 8th switch and the 3rd electric capacity, and the capacitance of described 3rd electric capacity is equal with the capacitance of described second electric capacity.
The first end of described 5th switch connects first input end and the output of described operational amplifier, the first end of described 6th switch connects the second input of described operational amplifier and the first end of the first electric capacity, second end of described 7th switch is suitable for inputting described first voltage, and the second end of described 8th switch is suitable for inputting described second voltage.In same second switch capacitor cell, the second end of described 5th switch connects the second end of described 6th switch and the first end of the 3rd electric capacity, and the first end of described 7th switch connects the first end of described 8th switch and the second end of the 3rd electric capacity.
The first switch described in the present embodiment, second switch, the 3rd switch and the 4th switch can be realized by the switch of same size, and described 5th switch, the 6th switch, the 7th switch and the 8th switch are also identical with the specification of the 4th switch with the first switch, second switch, the 3rd switch.So second switch capacitance group 2 is all identical with connected mode with the composition of the first switching capacity group 1.The increase of second switch capacitance group 2 can realize the mode of operation of duplex.
Concrete, described switch control unit is also suitable for output the 5th control signal, the 6th control signal, the 7th control signal and the 8th controls signal to needs the second switch capacitor cell of work to start the described second switch capacitor cell needing work.Described 5th control signal is suitable for the closed and disconnected controlling described 5th switch, described 6th control signal is suitable for the closed and disconnected controlling described 6th switch, described 7th control signal is suitable for the closed and disconnected controlling described 7th switch, and described 8th control signal is suitable for the closed and disconnected controlling described 8th switch.Described 5th control signal is the inversion signal of described first control signal, described 6th control signal is the inversion signal of described second control signal, described 7th control signal is the inversion signal of described 3rd control signal, and described 8th control signal is the inversion signal of described 4th control signal.
When only having the first switching capacity group 1 to work, the magnitude of voltage of the first electric capacity C1 first end Vramp only just increases when the first control signal is phase place 2, remains unchanged during phase place 1.And the first switching capacity group 1 and second switch capacitance group 2 are when all working, second electric capacity and the 3rd electric capacity are alternately to the first capacitor charging, the magnitude of voltage of the first electric capacity C1 first end Vramp can the first control signal be phase place 1 and phase place 2 time increase all to some extent, like this for given clock frequency and range of signal, the rise time of the magnitude of voltage of the first electric capacity C1 first end Vramp reduces half.And for given operating time and range of signal, clock frequency can reduce by one times, the time of that is setting up for signal in each phase place doubles.
Although the utility model discloses as above, the utility model is not defined in this.Any those skilled in the art, not departing from spirit and scope of the present utility model, all can make various changes or modifications, and therefore protection range of the present utility model should be as the criterion with claim limited range.
Claims (10)
1. a ramp generator, it is characterized in that, comprise: operational amplifier, first electric capacity and the first switching capacity group, described first switching capacity group comprises at least one first switching capacity unit, and described first switching capacity unit comprises: the first switch, second switch, the 3rd switch, the 4th switch and the second electric capacity;
The first end of described first switch connects negative-phase input and the output of described operational amplifier, the first end of described second switch connects the normal phase input end of described operational amplifier and the first end of the first electric capacity, second end of described 3rd switch is suitable for input first voltage, second end of described 4th switch is suitable for input second voltage, and the magnitude of voltage of described second voltage and the first voltage is unequal;
In same first switching capacity unit, the second end of described first switch connects the second end of described second switch and the first end of the second electric capacity, and the first end of described 3rd switch connects the described first end of the 4th switch and the second end of the second electric capacity;
Second end ground connection of described first electric capacity;
The capacitance of described first electric capacity is greater than the capacitance of described second electric capacity.
2. ramp generator as claimed in claim 1, it is characterized in that, also comprise: be suitable for output first control signal, the second control signal, the 3rd control signal and the 4th controls signal to needs the first switching capacity unit of work to start the described switch control unit needing the first switching capacity unit of work;
Described first control signal is suitable for the closed and disconnected controlling described first switch, described second control signal is suitable for the closed and disconnected controlling described second switch, described 3rd control signal is suitable for the closed and disconnected controlling described 3rd switch, and described 4th control signal is suitable for the closed and disconnected controlling described 4th switch;
Described second control signal is the inversion signal of described first control signal, and described 4th control signal is the inversion signal of described 3rd control signal, and described first control signal and the 3rd control signal are with frequency in-phase signal.
3. ramp generator as claimed in claim 2, it is characterized in that, the described quantity needing the first switching capacity unit of work is multiple, and described switch control unit is suitable for predetermined order and starts described the first switching capacity unit needing work successively.
4. ramp generator as claimed in claim 3, it is characterized in that, described predesigned order is relevant to the ramp signal slope that described ramp generator exports.
5. ramp generator as claimed in claim 3, it is characterized in that, described switch control unit is suitable for first exporting described second control signal and the 4th and controls signal to the first switching capacity unit all needing work, then exports described first control signal and the 3rd successively by described predesigned order and control signal to described the first switching capacity unit needing work.
6. ramp generator as claimed in claim 2, it is characterized in that, described first control signal and the second control signal are pulse signal, and the amplitude of described pulse signal is followed the first end magnitude of voltage increase of described first electric capacity and increases.
7. the ramp generator as described in claim as arbitrary in claim 2 to 6, it is characterized in that, also comprise second switch capacitance group, described second switch capacitance group comprises at least one second switch capacitor cell, described second switch capacitor cell comprises: the 5th switch, the 6th switch, the 7th switch, the 8th switch and the 3rd electric capacity, and the capacitance of described 3rd electric capacity is equal with the capacitance of described second electric capacity;
The first end of described 5th switch connects first input end and the output of described operational amplifier, the first end of described 6th switch connects the second input of described operational amplifier and the first end of the first electric capacity, second end of described 7th switch is suitable for inputting described first voltage, and the second end of described 8th switch is suitable for inputting described second voltage;
In same second switch capacitor cell, the second end of described 5th switch connects the second end of described 6th switch and the first end of the 3rd electric capacity, and the first end of described 7th switch connects the first end of described 8th switch and the second end of the 3rd electric capacity.
8. ramp generator as claimed in claim 7, it is characterized in that, described switch control unit is also suitable for output the 5th control signal, the 6th control signal, the 7th control signal and the 8th controls signal to needs the second switch capacitor cell of work to start the described second switch capacitor cell needing work;
Described 5th control signal is suitable for the closed and disconnected controlling described 5th switch, described 6th control signal is suitable for the closed and disconnected controlling described 6th switch, described 7th control signal is suitable for the closed and disconnected controlling described 7th switch, and described 8th control signal is suitable for the closed and disconnected controlling described 8th switch;
Described 5th control signal is the inversion signal of described first control signal, described 6th control signal is the inversion signal of described second control signal, described 7th control signal is the inversion signal of described 3rd control signal, and described 8th control signal is the inversion signal of described 4th control signal.
9. an imageing sensor, is characterized in that, comprising: the ramp generator described in the arbitrary claim of claim 1 to 8 and analog to digital converter, described ramp generator connects described analog to digital converter.
10. imageing sensor as claimed in claim 9, it is characterized in that, the required precision of described analog to digital converter is relevant to the capacitance ratio of described first electric capacity and the second electric capacity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420697134.9U CN204156831U (en) | 2014-11-19 | 2014-11-19 | Ramp generator and imageing sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104333352A (en) * | 2014-11-19 | 2015-02-04 | 格科微电子（上海）有限公司 | Ramp signal generating circuit and image sensor |
| CN109714082A (en) * | 2018-12-25 | 2019-05-03 | 中南大学 | A kind of dual mode transducer based on RF energy perception |
| CN115174882A (en) * | 2022-09-07 | 2022-10-11 | 天宜微电子(北京)有限公司 | Ramp signal module and gamma correction circuit |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104333352A (en) * | 2014-11-19 | 2015-02-04 | 格科微电子（上海）有限公司 | Ramp signal generating circuit and image sensor |
| CN104333352B (en) * | 2014-11-19 | 2016-12-07 | 格科微电子（上海）有限公司 | Ramp generator and imageing sensor |
| CN109714082A (en) * | 2018-12-25 | 2019-05-03 | 中南大学 | A kind of dual mode transducer based on RF energy perception |
| CN109714082B (en) * | 2018-12-25 | 2021-04-20 | 中南大学 | Dual-mode sensor based on radio frequency energy perception |
| CN115174882A (en) * | 2022-09-07 | 2022-10-11 | 天宜微电子(北京)有限公司 | Ramp signal module and gamma correction circuit |
| CN115174882B (en) * | 2022-09-07 | 2022-12-02 | 天宜微电子(北京)有限公司 | Ramp signal module and gamma correction circuit |
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