A domino logic circuit contained within an integrated circuit includes a dynamic logic circuit and an intermediate logic circuit. The intermediate logic circuit includes a pull-up transistor having a source terminal coupled to a source voltage line and an n-block transistor having a source terminal connected to a low ground voltage lin
A domino logic circuit contained within an integrated circuit includes a dynamic logic circuit and an intermediate logic circuit. The intermediate logic circuit includes a pull-up transistor having a source terminal coupled to a source voltage line and an n-block transistor having a source terminal connected to a low ground voltage line.
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A novel circuit technique for reducing leakage currents through the read-path of large register files in which a negative gate-source voltage is forced on a critical pass transistor between a cell read transistor and a local bitline such that when the cell is in a first state, the leakage current from a dynamic node of the cell read transistor is reduced. The reduced leakage current increases the robustness and performance of the read operation.
A method for controlling a local clock includes receiving a reference clock and generating a phase-shifted version of the reference clock. The two clocks are synchronized using a closed-loop method that produces a control signal. The control signal is smoothed during the closed-loop method and the smoothed signal is then used, instead of the control signal, in generating the phase-shifted clock
Increasing leakage currents combined with reduced noise margins are seriously degrading the robustness of dynamic circuits. This paper describes a dynamic implementation of a 256X32b 4-read/write-port Register-File for ~6GHz operation at 1.2V in a 0.13 utilize an efficient conditional keeper-technique, where a large fraction of the keeper is turned remains are able to improve upon all-low-Vt performance by 4%, while maintaining Dual-Vt usage. Thus, the robustness is improved by 96% and the active leakage power is reduced by 5X.
A dynamic circuit with a conditional keeper for burn-in. In the described embodiments, a conditional keeper is provided which is active only during the burn-in test, where the conditional keeper is sized larger than the standard keepers so as to compensate for additional leakage currents in the dynamic circuit.
A voltage-level converter and a method of converting a first logic voltage level to a second logic voltage level are described. In one embodiment, a voltage-level converter connects a first logic unit connected to a first supply voltage to a second logic unit connected to a second supply voltage. The voltage-level converter includes at least one transistor connected to the second supply voltage. The at least one transistor has a threshold voltage whose absolute value is greater-than-or-about-equal to the absolute value of the difference between the second supply voltage and the first supply voltage. In an alternative embodiment, a method for converting a first logic voltage level to a second logic voltage level includes transmitting a logic signal from a logic unit having an output voltage swing of between a first voltage level and a second voltage level, receiving the logic signal at a logic circuit having a pull-up transistor and an output voltage swing between a third voltage level and a fourth voltage level, and turning off the pull-up transistor when the logic signal has a value slightly greater than the difference between the third voltage level and the first voltage level.
Embodiments of the present invention relate to memory circuits with heavily loaded bit-lines, and where either the effect of leakage current in the read access or pass transistors is reduced, or leakage current is reduced.
Increasing leakage currents combined with reduced noise margins significantly degrade the robustness of wide dynamic circuits. In this paper, we describe two conditional keeper topologies for improving the robustness of sub-130-nm wide dynamic circuits. They are applicable in normal mode of operation as well as during burn-in test. A large fraction of the keepers is activated conditionally, allowing the use of strong keepers with leaky precharged circuits without significant impact on performance of the circuits. Compared to conventional techniques, up to 28% higher performance has been observed for wide dynamic gates in a 130-nm technology. In addition, the proposed burn-in keeper results in 64% active area reduction
A dual-rail static logic gate with a self cut-off mechanism is disclosed. In an embodiment, the output of the first rail is coupled to the input of the pull-up device of the second rail and vice versa. The cross-coupling allows the self cut-off mechanism of the static gate to function properly and provides for components which have lower capacitance than conventional static gates. The lower capacitance results in a faster static gate.
In this paper, interconnection length estimation is discussed and a general, simple, fast and efficient estimation technique is proposed. In contrast to traditional average length estimation techniques, such as the one based on Rent's rule, the new technique utilizes the topological information of the actual netlist and estimates the length of each interconnection separately. The result of the estimation can be directly used to assign a reasonable R and C to each interconnect, including long and wide buses. Consequently, the new technique enhances the accuracy of power and delay estimations at higher design levels of abstraction
In this paper, we present a new technique which indirectly separates and extracts the total short-circuit power consumption of digital CMOS circuits. We avoid a direct encounter with the complex behavior of the short-circuit currents. Instead, we separate the dynamic power consumption from the total power and extract the total short-circuit power. The technique is based on two facts: first, the short-circuit power consumption disappears at a Vdd close to VT and, secondly, the total capacitance depends on supply voltage in a sufficiently weak way in standard CMOS circuits. Hence, the total effective capacitance can be estimated at a low Vdd. To avoid reducing Vdd below the specified forbidden level, a polynomial is used to estimate the power versus supply voltage down to VT based on a small voltage sweep over the allowed supply voltage levels. The result shows good accuracy for the short-circuit current ranges of interest.
A sense amplifier for reading memory cells in a SRAM, the sense amplifier comprising two gate-biased pMOSFETs, each corresponding to a selected bitline. The gates of the two gate-biased pMOSFETs have their gates biased to a bias voltage, their sources coupled to the selected bitlines via column-select transistors, and their drains coupled via pass transistors to the two ports of two cross-coupled inverters, the cross-coupled inverters forming a latch. After a selected bitline pair has been pre-charged and the pre-charge phase ends, one of the two gate-biased pMOSFETs quickly goes into its subthreshold region as one of the bitlines discharges through its corresponding memory cell, thereby cutting off the bitline's capacitance from the sense amplifier. When the pass transistors are enabled, the other of the two pMOSFETs allows a significant bitline charge to transfer via its corresponding pass transistor to its corresponding port, whereas a relatively much smaller charge is transferred to the other port. This charge transfer scheme allows a differential voltage to quickly develop at the ports, thereby providing a fast latch and read operation with reduced power consumption. Bitline voltage swing may also be reduced to reduce power consumption.
A new wire estimation technique is presented. It utilizes the topology of the netlist and is sensitive to the actual design. It has the unique quality to estimate the length of every power consuming interconnection individually. Compared to other wire length estimation techniques which use average or total wire length, the result of the new technique shows a strong correlation with the result of "real" automatic placement and route tools. Hence it can estimate a reasonable wire capacitance for each interconnection. The individual wire lengths, combined with individual node activities, are essential for an accurate power estimation.
Many integrated circuit functional blocks, such as data and power converters, require timing and control signals consisting of complex sequences of pulses. Traditionally, these signals are generated from a clock signal using a combination of flip-flops, latches and delay elements. Due to the large internal switching activity of flips-flops and due to the many, effectively unused, clock cycles, this solution is inefficient from a power consumption point of view and is, therefore, unsuitable for ultralow-power applications. In this paper we present a method to generate non-overlapping control signals without using flip-flops or a clock. We propose to decode and translate the internal states of a ring oscillator into the desired control signal sequence. We show how this can be achieved using a simple combinatorial logic decoder. The proposed architecture significantly reduces the switching activity and the capacitive load, largely reducing the consumed power. We show an example implementation of a 9-bit SAR logic utilizing our proposed method. Furthermore, we show simulation results and compare the power consumption of the example SAR implementation to that of a functionally identical flip-flop-based state-of-the-art ultralow-power SAR. We were able to achieve a 5.8x reduction in consumed power for the complete SAR and 8x for the one-hot generation sub-part.
A high power single stage class E power amplifier is implemented with lumped elements at 0.89-1.02GHz using Silicon GaN High Electron Mobility Transistor as an active device. The maximum drain efficiency (DE) and power added efficiency (PAE) of 67 and 65 % respectively is obtained with a maximum output power of 42.2 dBm (~ 17 W) and amaximum power gain of 15 dB. We obtained good results at all measured frequencies.
This work presents an 11 GS/s 1.1 GHz bandwidth interleaved ΔΣ DAC in 65 nm CMOS for the 60 GHz radio baseband. The high sample rate is achieved by using a two-channel interleaved MASH 1–1 architecture with a 4 bit output resulting in a predominantly digital DAC with only 15 analog current cells. Two-channel interleaving allows the use of a single clock for the logic and the multiplexing which requires each channel to operate at half sampling rate of 5.5 GHz. To enable this, a look-ahead technique is proposed that decouples the two channels within the integrator feedback path thereby improving the speed as compared to conventional loop-unrolling. Measurement results show that the ΔΣ DAC achieves a 53 dB SFDR, -49 dBc IM3 and 39 dB SNDR within a 1.1 GHz bandwidth while consuming 117 mW from 1 V digital/1.2 V analog supplies. Furthermore, the proposed ΔΣ DAC can satisfy the spectral mask of the IEEE 802.11ad WiGig standard with a second order reconstruction filter.
Implementation of wireless wideband transmitters using ΔΣ DACs requires very high speed modulators. Digital MASH ΔΣ modulators are good candidates for speed enhancement using interleaving because they require only adders and can be cascaded. This paper presents an analysis of the integrator critical path of two-channel interleaved ΔΣ modulators. The bottlenecks for a high-speed operation are identified and the performance of different logic styles is compared. Static combinational logic shows the best trade-off and potential for use in such high speed modulators. A prototype 12-bit second order MASH ΔΣ modulator designed in 65 nm CMOS technology based on this study achieves 9 GHz operation at 1 V supply.
Time-interleaved ΔΣ DACs have the potential for wideband and high-speed operation. Their SNR is limited by the timing skew between the output delays of the channels to the output. In a two-channel interleaved ΔΣ DAC, the channel skew arises from the duty cycle error in the half sample rate clock. The effects of timing skew error can be mitigated by hold interleaving, digital pre-filtering or compensation in the form of analog post-correction or digital pre-correction. This paper presents a comparative study of these techniques for two-channel interleaving and the trade-offs are investigated. First order FIR pre-filtering is found to be a suitable solution with a moderate DAC matching penalty of one bit. Higher order pre-filtering achieves a near immunity to timing skew at the cost of higher matching penalty. Correction techniques are found to be less effective than pre-filtering and not well suited for high-speed implementation.
This brief presents an 8-GS/s 12-bit input ΔΣ digital-to-analog converter (DAC) with 200-MHz bandwidth in 65-nm CMOS. The high sampling rate is achieved by a two-channel interleaved MASH 1–1 digital ΔΣ modulator with 3-bit output, resulting in a highly digital DAC with only seven current cells. The two-channel interleaving allows the use of a single clock for both the logic and the final multiplexing. This requires each channel to operate at half the sampling rate, which is enabled by a high-speed pipelined MASH structure with robust static logic. Measurement results show that the DAC achieves 200-MHz bandwidth, 26-dB SNDR, and $-$57-dBc IMD3, with a power consumption of 68 mW at 1-V digital and 1.2-V analog supplies. This architecture shows potential for use in transmitter baseband for wideband wireless communication.
Time-interleaved delta-sigma (Delta Sigma) modulation digital-to-analog converters (TIDSM DACs) have the potential for a wideband operation. The performance of a two-channel interleaved Delta Sigma DAC is very sensitive to the duty cycle of the half-rate clock. This brief presents a closed-form expression for the signal-to-noise-plus-distortion ratio (SNDR) loss of such DACs due to a duty-cycle error for modulators with a noise transfer function of (1 - z(-1))(n). Adding a low-order finite-impulse-response filter after the modulator helps to mitigate this problem. A closed-form expression for the SNDR loss in the presence of this filter is also developed. These expressions are useful for choosing a suitable modulator and filter order for an interleaved Delta Sigma DAC in the early stage of the design process.
In this paper we present and carefully analyze a transition energy cost model aimed for efficient power estimation of performance critical deep submicron buses. We derive an accurate transition energy cost matrix, scalable to buses of arbitrary bit width, which includes properties that closer capture effects present in high-performance VLSI buses. The proposed energy model is verified against Spectre simulations of an implementable bus, including drivers. The average discrepancy between results from Spectre and the suggested model is limited to 4.5% when fringing effects of edge wires is neglected. The proposed energy model can account for effects that limit potential energy savings from bus transition coding.