Apple Inc.

Vivekanandan Venugopal

Ajay Bhatia

Michael R Seningen

Qi Ye

Suparn Vats

Suresh Balasubramanian

Raghava Rao V Denduluri

Gopinath Venkatesh

Teng Wang

Wenhao Li

Greg M Hess

Victor Zyuban

Hemangi Umakant Gajjewar

Shuyan Lei

Raymond Chang

Sneha Sindhu Matam

A memory circuit including a storage array circuit and a control circuit is disclosed. The control circuit may select a particular row of storage circuits in the storage array circuit and activate a first-stage circuit in a particular storage circuit in the particular row by coupling the first-stage circuit to a power supply node. At a later point in time, the control circuit may initiate a transfer of write data from the first-stage circuit to a second-stage circuit in the particular storage circuit and de-activate the first-stage circuit by de-coupling the first-stage circuit from the power supply node. Additionally, the control circuit may also de-select the particular row, at a different point in time, and maintain a de-activated state of the first-stage circuit until a subsequent selection of the particular row.

Power loss reduction in data storage arrays

An apparatus includes a control circuit configured to selectively activate, based on an operating mode signal, either a local clock signal or a pulse signal. The apparatus further includes a data storage circuit that is coupled to a data signal, the local clock signal, and the pulse signal. The data storage circuit may be configured to sample the data signal using the local clock signal during a first operating mode, and to sample the data signal using the pulse signal during a second operating mode.

Hybrid pulse/two-stage data latch

A power detection circuit for detecting powering down of a voltage domain in an integrated circuit is disclosed. The power detection circuit is placed in or near the voltage domain in the integrated circuit to provide power detection on the integrated circuit. The power detection circuit detects powering down of the voltage domain to provide an isolation enable signal to another voltage domain that interfaces with the powering down voltage domain. The isolation enable signal may be used by an isolation cell coupled to the non-powering down voltage domain to prevent corrupted logic being received from the powering down voltage domain.

Power down detection for non-destructive isolation signal generation

A flip-flop with glitch protection is disclosed. The flip-flop includes a differential amplifier circuit that generates amplifier output signals based on an input data and clock signals and precharges a true data node when a clock signal is inactive. A latch circuit is coupled to the differential amplifier and includes a latch node. Responsive to a current value of the input data signal having a first logic state, the latch node is set at a logic value equivalent to the precharged value during an active phase of the clock signal. Responsive to the current value of the input data signal having a second logic state complementary to the first, during the active phase of the clock signal, the latch circuit causes the latch node to be set to a logic value complementary to the precharged value, using the clock signal and the current value of the input data signal.

Flip-flop circuit with glitch protection

Systems, apparatuses, and methods for implementing low voltage clock swing sequential circuits are described. An input signal is coupled to the gates of a first P-type transistor and a first N-type transistor of a first transistor stack. A low voltage swing clock signal is coupled to the gate of a second N-type transistor of the first transistor stack. An inverse of the input signal is coupled to the gates of a second P-type transistor and a third N-type transistor of a second transistor stack. The low-swing clock is coupled to the gate of a fourth N-type transistor of the second transistor stack. A first end of one or more enabling P-Type transistors with gates coupled to the low-swing clock is coupled to the first P-type transistor's drain, and a second end of the one or more enabling P-Type transistors is coupled to the second P-type transistor's drain.

Low voltage clock swing tolerant sequential circuits for dynamic power savings

A system and method for efficiently retaining data in sequential elements during power down modes. In various embodiments, a master latch of a flip-flop circuit receives an always-on first power supply voltage, whereas, a slave latch and other surrounding circuitry receives a second power supply voltage capable of being powered down. During a power down mode, circuitry consumes less power while the master latch retains stored data. In some designs, the flip-flop circuit is a level shifting circuit, and the always-on first power supply voltage is less than the second power supply voltage. The master latch uses complex gates with a p-type transistor at the top of a stack of p-type transistors receiving the always-on power supply voltage level on its source terminal and the retained data value on its gate terminal. This top p-type transistor is capable of remaining disabled even when used in a level shifting manner.

Efficient retention flop utilizing different voltage domain

Systems, apparatuses, and methods for implementing a low-power, single-pin retention flip-flop with a balloon latch are described. A flip-flop is connected to a retention latch to store a value of the flip-flop during a reduced power state. A single retention pin is used to turn on the retention latch. During normal mode, the retention latch is pre-charged and a change in the value stored by the flip-flop does not cause the retention latch to toggle. This helps to reduce the power consumed by the circuit during normal mode (i.e., non-retention mode). When the retention signal becomes active, the retention latch gets triggered and the value stored by the flip-flop is written into the retention latch. Later, if the flip-flop is powered down and then powered back up while the circuit is in retention mode, the value in the retention latch gets written back into the flip-flop.

Low power single retention pin flip-flop with balloon latch

A system and method for efficiently storing and driving data between pipeline stages. In various embodiments, a flip-flop circuit includes a bypass circuit, which is a tri-state inverter, and the bypass circuit receives a clock signal and a version of a data signal. When the clock signal received by the flip-flop circuit is asserted, the output of the bypass circuit is sent as the output of the flip-flop circuit. In one example, the version of the data signal received by the bypass circuit is the data signal. In another example, the version of the data signal received by the bypass circuit is the output of a master latch. Although the output of the master latch is pre-charged, when the clock is asserted, each of a late arriving rising and falling data transition are included in the critical path of the flip-flop circuit.

Semi dynamic flop and single stage pulse flop with shadow latch and transparency on both input data edges

Systems, apparatuses, and methods for implementing a high-performance clock-gating circuit are described. A first pull-down stack receives enable and pulse signals on gates of N-type transistors which pull down an output node when the enable and pulse signals are both high. A pull-up transistor coupled to the output node receives a clock signal which turns off the pull-up transistor when the clock signal is high. A first pull-up stack receives the inverted pulse signal and the enable signal on gates of P-type transistors to cause the output node to be high when the enable signal and inverted pulse signal are low. A second pull-up stack maintains a high voltage on the output node after the pulse event has ended but while the clock signal is still high. A second pull-down stack maintains a low voltage on the output node after the pulse event but while the clock remains high.

No-enable setup clock gater based on pulse

Techniques are disclosed relating to level-shifting circuitry and time borrowing across voltage domains. In some embodiments, sense amplifier circuitry generates, based on an input signal at a first voltage level, an output signal at a second, different voltage level. Pulse circuitry may generate a pulse signal in response to an active clock edge of a clock signal that is input to the sense amplifier circuitry. Initial resolution circuitry may drive the output signal of the sense amplifier circuitry to match the value of the input signal during the pulse signal. Secondary resolution circuitry may maintain a current value of the output signal after expiration of the pulse signal. This may allow the input signal to change during the pulse, e.g., to enable time borrowing by upstream circuitry.

Level-shifting transparent window sense amplifier

Systems, apparatuses, and methods for implementing low-power flip-flops with balanced clock-to-Q delay are described. A flip-flop includes a primary latch, an upper secondary latch, and a lower secondary latch. The primary latch transmits a data value from an input port to a first node when transparent. The upper secondary latch pulls up a second node when transparent and when the first node is equal to a first value. The second node is a prebuffered data output of the flip-flop. The lower secondary latch pulls down the second node when transparent and when the first node is equal to a second value different from the first value. To ensure the flip-flop has a balanced clock-to-Q delay, a first set of clock signals coupled to transistor gates of the primary latch are delayed with respect to a second set of clock signals coupled to transistor gates of the upper secondary latch.

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San Jose, CA, United States of America

Vivekanandan Venugopal